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Physics: Principles with Applications | 6th Edition | ISBN: 9780130606204 | Authors: Douglas C. Giancoli
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Physics: Principles with Applications 6th Edition solutions

Author: Douglas C. Giancoli
Publisher: Pearson/Prentice Hall
ISBN: 9780130606204

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Chapter 19 Problems

Chapter: 19 Problem: 15Q

Physics: Principles with Applications 6
According to Newton's third law, each team in a tug of war (Fig. 4-37) pulls with equal force on the other team. What, then, determines which team will win?

Chapter: 19 Problem: 1P

Physics: Principles with Applications 6
Problem 1P What force is needed to accelerate a child on a sled (total mass = 60.0 kg) at 1.25 m/s2?

Chapter: 19 Problem: 2P

Physics: Principles with Applications 6
Problem 2P A net force of 265 N accelerates a bike and rider at 2.30 m/s2. What is the mass of the bike and rider together?

Chapter: 19 Problem: 7Q

Physics: Principles with Applications 6
Problem 7Q Why might your foot hurt if you kick a heavy desk or a wall?

Chapter: 19 Problem: 8Q

Physics: Principles with Applications 6
Problem 8Q When you are running and want to stop quickly, you must decelerate quickly. (a) What is the origin of the force that causes you to stop? (b) Estimate (using your own experience) the maximum rate of deceleration of a person running at top speed to come to rest.

Chapter: 19 Problem: 11Q

Physics: Principles with Applications 6
Problem 11Q Would a spring scale carried to the Moon give accurate results if the scale had been calibrated (a) in pounds, or (b) in kilograms?

Chapter: 19 Problem: 12P

Physics: Principles with Applications 6
Problem 12P A 12.0-kg bucket is lowered vertically by a rope in which there is 163 N of tension at a given instant. What is the acceleration of the bucket? Is it up or down?

Chapter: 19 Problem: 46P

Physics: Principles with Applications 6
(II) For the system of Fig. 4-32 (Example 4-20), how large a mass would box A have to have to prevent any motion from occurring? Assume \(\mu_{s}=0.30\). Equation Transcription: Text Transcription: \mu_{s}=0.30

Chapter: 19 Problem: 15P

Physics: Principles with Applications 6
A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.75 of the persons regular weight. Calculate the acceleration of the elevator, and find the direction of acceleration.

Chapter: 19 Problem: 16Q

Physics: Principles with Applications 6
Problem 16Q A person exerts an upward force of 40 N to hold a bag of groceries. Describe the reaction force (Newtons third law) by stating (a) its magnitude, (b) its direction, (c) on what object it is exerted, and (d) by what object it is exerted.

Chapter: 19 Problem: 18P

Physics: Principles with Applications 6
(II) A person jumps from the roof of a house 3.9-m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 m. If the mass of his torso (excluding legs) is 42 kg, find (a) his velocity just before his feet strike the ground, and (b)

Chapter: 19 Problem: 20P

Physics: Principles with Applications 6
(I) Draw the free-body diagram for a basketball player (?) just before leaving the ground on a jump, and (b) while in the air. See Fig. 441.

Chapter: 19 Problem: 22P

Physics: Principles with Applications 6
(I) A 650-N force acts in a northwesterly direction. A second 650-N force must be exerted in what direction so that the resultant of the two forces points westward? Illustrate your answer with a vector diagram.

Chapter: 19 Problem: 24P

Physics: Principles with Applications 6
(II) The two forces \(\vec{F}_{1} \text { and } \vec{F}_{2}\) shown in Fig. 443a and b (looking down) act on a 27.0-kg object on a frictionless tabletop. If \(F_{1}=10.2 \mathrm{~N} \text { and } F_{2}=16.0 \mathrm{~N}\), find the net force on the object and its acceleration for (a) and (b).

Chapter: 19 Problem: 25P

Physics: Principles with Applications 6
Problem 25P One 3.2-kg paint bucket is hanging by a massless cord from another 3.2-kg paint bucket, also hanging by a mass-less cord, as shown in Fig. 444. (a) If the buckets are at rest, what is the tension in each cord? (b) If the two buckets are pulled upward with an acceleration of 1.60 m/s2by

Chapter: 19 Problem: 29P

Physics: Principles with Applications 6
(II) A window washer pulls herself upward using the bucket-pulley apparatus shown in Fig. 448. (a) How hard must she pull downward to raise herself slowly at constant speed? (b) If she increases this force by 15%, what will her acceleration be? The mass of the person plus the bucket is 65 kg.

Chapter: 19 Problem: 32P

Physics: Principles with Applications 6
(II) A pair of fuzzy dice is hanging by a string from your rearview mirror. While you are accelerating from a stoplight to \(28 \mathrm{~m} / \mathrm{s}\) in \(6.0 \mathrm{~s}\), what angle \(\theta\) does the string make with the vertical? See Fig. 4-50.

Chapter: 19 Problem: 33P

Physics: Principles with Applications 6
(III) Three blocks on a frictionless horizontal surface are in contact with each other, as shown in Fig. 451. A force \(\vec{F}\) is applied to block A \(\left(\text { mass } m_{A}\right)\). (a) Draw a free-body diagram for each block. Determine (b) the acceleration of the system (in terms of

Chapter: 19 Problem: 34P

Physics: Principles with Applications 6
(III) The two masses shown in Fig. 452 are each initially 1.80 m above the ground, and the massless frictionless pulley is 4.8 m above the ground. What maximum height does the lighter object reach after the system is released? [Hint: First determine the acceleration of the lighter mass and then its v

Chapter: 19 Problem: 35P

Physics: Principles with Applications 6
(III) Suppose two boxes on a frictionless table are connected by a heavy cord of mass 1.0 kg. Calculate the acceleration of each box and the tension at each end of the cord, using the free-body diagrams shown in Fig. 453. Assume \(F_{P}=40.0 \mathrm{~N}\), and ignore sagging of the cord. Compare your

Chapter: 19 Problem: 36P

Physics: Principles with Applications 6
Problem 36P If the coefficient of kinetic friction between a 35-kg crate and the floor is 0.30, what horizontal force is required to move the crate at a steady speed across the floor? What horizontal force is required if ?k is zero?

Chapter: 19 Problem: 37P

Physics: Principles with Applications 6
Problem 37P A force of 48.0 N is required to start a 5.0-kg box moving across a horizontal concrete floor. (a) What is the coefficient of static friction between the box and the floor? (b) If the 48.0-N force continues, the box accelerates at 0.70 m/s2. What is the coefficient of kinetic friction?

Chapter: 19 Problem: 40P

Physics: Principles with Applications 6
(II) The coefficient of static friction between hard rubber and normal street pavement is about 0.8. On how steep a hill (maximum angle) can you leave a car parked?

Chapter: 19 Problem: 39P

Physics: Principles with Applications 6
Problem 39P What is the maximum acceleration a car can undergo if the coefficient of static friction between the tires and the ground is 0.80?

Chapter: 19 Problem: 41P

Physics: Principles with Applications 6
(II) A 15.0-kg box is released on a \(32^{\circ}\) incline and accelerates down the incline at \(0.30 \mathrm{~m} / \mathrm{s}^{2}\). Find the friction force impeding its motion. What is the coefficient of kinetic friction? Equation Transcription:

Chapter: 19 Problem: 42P

Physics: Principles with Applications 6
(II) A car can decelerate at \(?4.80 m/s^2\) without skidding when coming to rest on a level road. What would its deceleration be if the road were inclined at \(13^{\circ}\) uphill? Assume the same static friction coefficient.

Chapter: 19 Problem: 84GP

Physics: Principles with Applications 6
Two rock climbers, Jim and Karen, use safety ropes of similar length. Karen's rope is more elastic, called a dynamic rope by climbers. Jim has a static rope, not recommended for safety purposes in pro climbing, (a) Karen (Fig. 4-71) falls freely about 2.0 m and then the rope stops her over a distance

Chapter: 19 Problem: 43P

Physics: Principles with Applications 6
Problem 43P (a) A box sits at rest on a rough 30 inclined plane. Draw the free-body diagram, showing all the forces acting on the box. (b) How would the diagram change if the box were sliding down the plane? (c) How would it change if the box were sliding up the plane after an initial shove?

Chapter: 19 Problem: 45P

Physics: Principles with Applications 6
(II) The coefficient of kinetic friction for a 22-kg bobsled on a track is 0.10. What force is required to push it down a \(6.0^\circ\) incline and achieve a speed of 60 km/h at the end of 75 m?

Chapter: 19 Problem: 47P

Physics: Principles with Applications 6
(II) A box is given a push so that it slides across the floor. How far will it go, given that the coefficient of kinetic friction is 0.20 and the push imparts an initial speed of \(4.0 \mathrm{~m} / \mathrm{s}\)?

Chapter: 19 Problem: 48P

Physics: Principles with Applications 6
(II) Two crates, of mass 75 kg and 110 kg, are in contact and at rest on a horizontal surface (Fig. 454). A 620-N force is exerted on the 75-kg crate. If the coefficient of kinetic friction is 0.15, calculate (a) the acceleration of the system, and (b) the force that each crate exerts on the other. (

Chapter: 19 Problem: 49P

Physics: Principles with Applications 6
Problem 49P A flatbed truck is carrying a heavy crate. The coefficient of static friction between the crate and the bed of the truck is 0.75. What is the maximum rate at which the driver can decelerate and still avoid having the crate slide against the cab of the truck?

Chapter: 19 Problem: 50P

Physics: Principles with Applications 6
(II) On an icy day, you worry about parking your car in your driveway, which has an incline of \(12^\circ\). Your neighbors driveway has an incline of \(9.0^\circ\), and the driveway across the street is at \(6.0^\circ\). The coefficient of static friction between tire rubber and ice is 0.15. Which d

Chapter: 19 Problem: 51P

Physics: Principles with Applications 6
Problem 51P A child slides down a slide with a 28 incline, and at the bottom her speed is precisely half what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child.

Chapter: 19 Problem: 52P

Physics: Principles with Applications 6
(II) The carton shown in Fig. 455 lies on a plane tilted at an angle \(\theta=22.0^{\circ}\) to the horizontal, with \(\mu_{k}=0.12\) (a) Determine the acceleration of the carton as it slides down the plane. (b) If the carton starts from rest 9.30 m up the plane from its base, what will

Chapter: 19 Problem: 54P

Physics: Principles with Applications 6
(II) A roller coaster reaches the top of the steepest hill with a speed of \(6.0 \mathrm{~km} / \mathrm{h}\). It then descends the hill, which is at an average angle of \(45^{\circ}\) and is \(45.0 \mathrm{~m}\) long. Estimate its speed when it reaches the bottom. Assume \(\mu_{\mathrm{k}}=0.18\).

Chapter: 19 Problem: 53P

Physics: Principles with Applications 6
(II) A carton is given an initial speed of \(3.0 \mathrm{~m} / \mathrm{s}\) up the \(22.0^{\circ}\) plane shown in Fig. 455. (a) How far up the plane will it go? (b) How much time elapses before it returns to its starting point? Ignore friction.

Chapter: 19 Problem: 55P

Physics: Principles with Applications 6
(II) An 18.0-kg box is released on a \(37.0^\circ\) incline and accelerates down the incline at \(0.270 \ \mathrm {m/s}^2\). Find the friction force impeding its motion. How large is the coefficient of kinetic friction?

Chapter: 19 Problem: 56P

Physics: Principles with Applications 6
(II) A small box is held in place against a rough wall by someone pushing on it with a force directed upward at \(28^{\circ}\) above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.40 and 0.30, respectively. The box slides down unless the applied force h

Chapter: 19 Problem: 57P

Physics: Principles with Applications 6
Problem 57P Piles of snow on slippery roofs can become dangerous projectiles as they melt. Consider a chunk of snow at the ridge of a roof with a pitch of 30. (a) What is the minimum value of the coefficient of static friction that will keep the snow from sliding down? (b) As the snow begins to mel

Chapter: 19 Problem: 58P

Physics: Principles with Applications 6
Problem 58P (a) Show that the minimum stopping distance for an automobile traveling at speed v is equal to v2/2/?s g, where ?s is the coefficient of static friction between the tires and the road, and g is the acceleration of gravity. (b) What is this distance for a 1200-kg car traveling 95 km/h if

Chapter: 19 Problem: 59P

Physics: Principles with Applications 6
Problem 59P A coffee cup on the dashboard of a car slides forward on the dash , when the driver decelerates from 45 km/h to rest in 3.5 s or less, but not if he decelerates in a longer time. What is the coefficient of static friction between the cup and the dash?

Chapter: 19 Problem: 60P

Physics: Principles with Applications 6
Problem 60P A small block of mass m is given an initial speed v0 up a ramp inclined at angle ? to the horizontal. It travels a distance d up the ramp and comes to rest. Determine a formula for the coefficient of kinetic friction between block and ramp.

Chapter: 19 Problem: 61P

Physics: Principles with Applications 6
(III) The 75-kg climber in Fig. 456 is supported in the chimney by the friction forces exerted on his shoes and back. The static coefficients of friction between his shoes and the wall, and between his back and the wall, are 0.80 and 0.60, respectively. What is the minimum normal force he must exert?

Chapter: 19 Problem: 62P

Physics: Principles with Applications 6
Problem 62P Boxes are moved on a conveyor belt from where they are filled to the packing station 11.0m away. The belt is initially stationary and must finish with zero speed. The most rapid transit is accomplished if the belt accelerates for half the distance, then decelerates for the final half of

Chapter: 19 Problem: 64P

Physics: Principles with Applications 6
(III) (a) Suppose the coefficient of kinetic friction between m1, and the plane in Fig. 457 is \(\mu_{k}=0.15\), and that \(m_{1}=m_{2}=2.7 \mathrm{~kg}\). As \(m_{2}\) moves down, determine the magnitude of the acceleration of \(m_{1} \text { and } m_{2}\), given \(\theta=25^{\circ}\).

Chapter: 19 Problem: 63P

Physics: Principles with Applications 6
(III) A block \(\text { (mass } m_{1} \text { ) } \) lying on a frictionless inclined plane is connected to a mass \(m_{2}\) by a massless cord passing over a pulley, as shown in Fig. 457. (a) Determine a formula for the acceleration of the system of the two blocks in terms of \(m_{1}, m_{2},

Chapter: 19 Problem: 65P

Physics: Principles with Applications 6
Problem 65P A bicyclist of mass 65 kg (including the bicycle) can coast down a 6.0 hill at a steady speed of 6.0 km/h because of air resistance. How much force must be applied to climb the hill at the same speed and same air resistance?

Chapter: 19 Problem: 69GP

Physics: Principles with Applications 6
An 1150-kg car pulls a 450-kg trailer. The car exerts a horizontal force of \(3.8 \times 10^{3} N\) against the ground in order to accelerate. What force does the car exert on the trailer? Assume an effective friction coefficient of 0.15 for the trailer.

Chapter: 19 Problem: 72GP

Physics: Principles with Applications 6
A 2.0-kg purse is dropped from the top of the Leaning Tower of Pisa and falls 55 m before reaching the ground with a speed of 29 m/s. What was the average force of air resistance?

Chapter: 19 Problem: 73GP

Physics: Principles with Applications 6
Problem 73GP A cyclist is coasting at a steady speed of 12 m/s but enters a muddy stretch where the effective coefficient of friction is 0.60. Will the cyclist emerge from the muddy stretch without having to pedal if the mud lasts for 11 m? If so, what will be the speed upon emerging?

Chapter: 19 Problem: 74GP

Physics: Principles with Applications 6
A city planner is working on the redesign of a hilly portion of a city. An important consideration is how steep the roads can be so that even low-powered cars can get up the hills without slowing down. A particular small car, with a mass of 1100 kg, can accelerate on a level road from rest to 21 m/s

Chapter: 19 Problem: 75GP

Physics: Principles with Applications 6
Francesca, who likes physics experiments, dangles her watch from a thin piece of string while the jetliner she is in takes off from JFK Airport (Fig. 458). She notices that the string makes an angle of 25 with respect to the vertical as the aircraft accelerates for takeoff, which takes about 18 s. Es

Chapter: 19 Problem: 76GP

Physics: Principles with Applications 6
A 28.0-kg block is connected to an empty 1.35-kg bucket by a cord running over a frictionless pulley (Fig. 459). The coefficient of static friction between the table and the block is 0.450 and the coefficient of kinetic friction between the table and the block is 0.320. Sand is gradually added to the

Chapter: 19 Problem: 77GP

Physics: Principles with Applications 6
Problem 77GP In the design of a supermarket, there are to be several ramps connecting different parts of the store. Customers will have to push grocery carts up the ramps and it is obviously desirable that this not be too difficult. The engineer has done a survey and found that almost no one compla

Chapter: 19 Problem: 79GP

Physics: Principles with Applications 6
A jet aircraft is accelerating at \(3.5 \ \mathrm{m/s}^2\) at an angle of \(45^\circ\) above the horizontal. What is the total force that the cockpit seat exerts on the 75-kg pilot?

Chapter: 19 Problem: 80GP

Physics: Principles with Applications 6
In the design process for a child-restraint chair, an engineer considers the following set of conditions: A 12-kg child is riding in the chair, which is securely fastened to the seat of an automobile (Fig. 461). Assume the automobile is involved in a head-on collision with another vehicle. The initia

Chapter: 19 Problem: 81GP

Physics: Principles with Applications 6
A 7650-kg helicopter accelerates upward at \(0.80 \mathrm{~m} / \mathrm{s}^{2}\) while lifting a 1250-kg frame at a construction site, Fig. 462. (a) What is the lift force exerted by the air on the helicopter rotors? (b) What is the tension in the cable (ignore its mass) that connects the f

Chapter: 19 Problem: 82GP

Physics: Principles with Applications 6
Problem 82GP A super high-speed 12-car Italian train has a mass of 660 metric tons (660,000 kg). It can exert a maximum force of 400 kN horizontally against the tracks, whereas at maximum velocity (300 km/h), it exerts a force of about 150 kN. Calculate (a) its maximum acceleration, and (b) estimat

Chapter: 19 Problem: 86GP

Physics: Principles with Applications 6
Problem 86GP An elevator in a tall building is allowed to reach a maximum speed of 3.5 m/s going down. What must the tension be in the cable to stop this elevator over a distance of 2.6 m if the elevator has a mass of 1300 kg including occupants?

Chapter: 19 Problem: 87GP

Physics: Principles with Applications 6
Two boxes, \(m_{1}=1.0 \mathrm{~kg}\) with a coefficient of kinetic friction of 0.10, and \(m_{2}=2.0 \mathrm{~kg}\) with a coefficient of 0.20, are placed on a plane inclined at \(\theta=30^{\circ}\) (a) What acceleration does each box experience? (b) If a taut string is connected to

Chapter: 19 Problem: 88GP

Physics: Principles with Applications 6
Problem 88GP A 75.0-kg person stands on a scale in an elevator. What does the scale read (in N and in kg) when the elevator is (a) at rest, (b) ascending at a constant speed of 3.0 m/s, (c) falling at 3.0 m/s, (d) accelerating upward at 3.0 m/s2, (e) accelerating downward at 3.0 m/s2?

Chapter: 19 Problem: 89GP

Physics: Principles with Applications 6
Three mountain climbers who are roped together are ascending an icefield inclined at \(21.0^\circ\) to the horizontal. The last climber slips, pulling the second climber off his feet. The first climber is able to hold them both. If each climber has a mass of 75 kg, calculate the tension in each of th

Chapter: 19 Problem: 1Q

Physics: Principles with Applications 6
Problem 1Q Why does a child in a wagon seem to fall backward when you give the wagon a sharp pull forward?

Chapter: 19 Problem: 2Q

Physics: Principles with Applications 6
A box rests on the (frictionless) bed of a truck. The truck driver starts the truck and accelerates forward. The box immediately starts to slide toward the rear of the truck bed. Discuss the motion of the box, in terms of Newton's laws, as seen ( ) by Mary standing on the ground beside the truck, an

Chapter: 19 Problem: 3Q

Physics: Principles with Applications 6
Problem 3Q If the acceleration of an object is zero, are no forces acting on it? Explain.

Chapter: 19 Problem: 4Q

Physics: Principles with Applications 6
Problem 4Q Only one force acts on an object. Can the object have zero acceleration? Can it have zero velocity? Explain.

Chapter: 19 Problem: 5Q

Physics: Principles with Applications 6
Problem 5Q Problem When a golf ball is dropped to the pavement, it bounces back up. (a) Is a force needed to make it bounce back up? (b) If so, what exerts the force?

Chapter: 19 Problem: 6Q

Physics: Principles with Applications 6
Problem 6Q Problem If you walk along a log floating on a lake, why does the log move in the opposite direction?

Chapter: 19 Problem: 9Q

Physics: Principles with Applications 6
A stone hangs by a fine thread from the ceiling, and a section of the same thread dangles from the bottom of the stone (Fig. ). If a person gives a sharp pull on the dangling thread, where is the thread likely to break: below the stone or above it? What if the person gives a slow and steady pull? Ex

Chapter: 19 Problem: 10Q

Physics: Principles with Applications 6
Problem 10Q Problem The force of gravity on a 2-kg rock is twice as great as that on a 1 -kg rock. Why then doesn't the heavier rock fall faster?

Chapter: 19 Problem: 12Q

Physics: Principles with Applications 6
Problem 12Q Problem (a) You pull a box with a constant force across a frictionless table using an attached rope held horizontally. If you now pull the rope with the same force at an angle to the horizontal (with the box remaining flat on the table), does the acceleration of the box increase, decre

Chapter: 19 Problem: 13P

Physics: Principles with Applications 6
Problem 13P Problem (II) An elevator (mass 4850 kg) is to be designed so that the maximum acceleration is 0.0680g. What are the maximum and minimum forces the motor should exert on the supporting cable?

Chapter: 19 Problem: 13Q

Physics: Principles with Applications 6
Problem 13Q Problem When an object falls freely under the influence of gravity there is a net force mg exerted on it by the Earth. Yet by Newton's third law the object exerts an equal and opposite force on the Earth. Does the Earth move? Explain.

Chapter: 19 Problem: 14P

Physics: Principles with Applications 6
Problem 14P Problem (II) A 75-kg petty thief wants to escape from a third-story jail window. Unfortunately, a makeshift rope made of sheets tied together can support a mass of only 53 kg. How might the thief use this "rope" to escape? Give a quantitative answer.

Chapter: 19 Problem: 14Q

Physics: Principles with Applications 6
Problem 14Q Problem Compare the effort (or force) needed to lift a 10-kg object when you are on the Moon with the force needed to lift it on Earth. Compare the force needed to throw a 2-kg object horizontally with a given speed on the Moon and on Earth.

Chapter: 19 Problem: 16P

Physics: Principles with Applications 6
Problem 16P Problem (II) The cable supporting a 2125-kg elevator has a maximum strength of 21,750 N. What maximum upward acceleration can it give the elevator without breaking?

Chapter: 19 Problem: 17P

Physics: Principles with Applications 6
(II) (a) What is the acceleration of two falling sky divers (mass including parachute) when the upward force of air resistance is equal to one-fourth of their weight? ( ) After popping open the parachute, the divers descend leisurely to the ground at constant speed. What now is the force of air res

Chapter: 19 Problem: 17Q

Physics: Principles with Applications 6
Problem 17Q Problem When you stand still on the ground, how large a force does the ground exert on you? Why doesn't this force make you rise up into the air?

Chapter: 19 Problem: 18Q

Physics: Principles with Applications 6
Problem 18Q Problem Whiplash sometimes results from an automobile accident when the victim's car is struck violently from the rear. Explain why the head of the victim seems to be thrown backward in this situation. Is it really?

Chapter: 19 Problem: 19P

Physics: Principles with Applications 6
(I) A box weighing rests on a table. A rope tied to the box runs vertically upward over a pulley and a weight is hung from the other end (Fig. 4-40). Determine the force that the table exerts on the box if the weight hanging on the other side of the pulley weighs a) , and .

Chapter: 19 Problem: 19Q

Physics: Principles with Applications 6
Problem 19Q Problem A heavy crate rests on the bed of a flatbed truck. When the truck accelerates, the crate stays fixed on the truck, so it, too, accelerates. What force causes the crate to accelerate?

Chapter: 19 Problem: 20Q

Physics: Principles with Applications 6
Problem 20Q Problem A block is given a brief push so that it slides up a ramp. After the block reaches its highest point, it slides back down, but the magnitude of its acceleration is less on the descent than on the ascent. Why?

Chapter: 19 Problem: 21P

Physics: Principles with Applications 6
Problem 21P Problem (I) Sketch the free-body diagram of a baseball (a) at the moment it is hit by the bat, and again (b) after it has left the bat and is flying toward the outfield. Ignore air resistance.

Chapter: 19 Problem: 21Q

Physics: Principles with Applications 6
Problem 21Q Problem What would your bathroom scale read if you weighed yourself on an inclined plane? Assume the mechanism functions properly, even at an angle.

Chapter: 19 Problem: 23P

Physics: Principles with Applications 6
(II) Arlene is to walk across a "high wire" strung horizontally between two buildings apart. The sag in the rope when she is at the midpoint is , as shown in Fig. . If her mass is , what is the tension in the rope at this point?

Chapter: 19 Problem: 26P

Physics: Principles with Applications 6
(II) A person pushes a lawn mower at constant speed with a force of directed along the handle, which is at an angle of \(45.0^{\circ}\) to the horizontal (Fig. . (a) Draw the free-body diagram showing all forces acting on the mower. Calculate (b) the horizontal friction force on the mower, th

Chapter: 19 Problem: 27P

Physics: Principles with Applications 6
(II) Two snowcats tow a housing unit to a new location at McMurdo Base, Antarctica, as shown in Fig. The sum of the forces \(\vec{F}_{A} \text { and } \vec{F}_{B}\) exerted on the unit by the horizontal cables is parallel to the line , and \(F_{A}=4500 N\). Determine \(F_{B}) and the magnitude of \(

Chapter: 19 Problem: 28P

Physics: Principles with Applications 6
(II) A train locomotive is pulling two cars of the same mass behind it, Fig. Determine the ratio of the tension in the coupling between the locomotive and the first car \(\left(F_{T 1}\right)\), to that between the first car and the second car \(\left(F_{T 2}\right)\), for any nonzero acceleration o

Chapter: 19 Problem: 30P

Physics: Principles with Applications 6
(II) At the instant a race began, a 65-kg sprinter exerted a force of 720 N on the starting block at a \(22^{\circ}\) angle with respect to the ground, (a) What was the horizontal acceleration of the sprinter? (b) If the force was exerted for 0.32 s, with what speed did the sprinter leave t

Chapter: 19 Problem: 31P

Physics: Principles with Applications 6
(II) Figure shows a block (mass \(m_{A}\) ) on a smooth horizontal surface, connected by a thin cord that passes over a pulley to a second block \(\left(m_{B}\right)\), which hangs vertically. (a) Draw a free-body diagram for each block, showing the force of gravity on each, the force (tension) e

Chapter: 19 Problem: 38P

Physics: Principles with Applications 6
Problem 38P Problem (I) Suppose you are standing on a train accelerating at 0.20 g. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide?

Chapter: 19 Problem: 44P

Physics: Principles with Applications 6
Problem 44P Problem (II) Drag-race tires in contact with an asphalt surface have a very high coefficient of static friction. Assuming a constant acceleration and no slipping of tires, estimate the coefficient of static friction needed for a drag racer to cover 1.0 km in 12 s, starting from rest.

Chapter: 19 Problem: 66GP

Physics: Principles with Applications 6
Problem 66GP (II) According to a simplified model of a mammalian heart, at each pulse approximately 20 g of blood is accelerated from 0.25 m/s to 0.35 m/s during a period of 0.10 s. What is the magnitude of the force exerted by the heart muscle?

Chapter: 19 Problem: 70GP

Physics: Principles with Applications 6
Problem 70GP Problem (II) Police investigators, examining the scene of an accident involving two cars, measure 72-m-long skid marks of one of the cars, which nearly came to a stop before colliding. The coefficient of kinetic friction between rubber and the pavement is about 0.80. Estimate the init

Chapter: 19 Problem: 71GP

Physics: Principles with Applications 6
Problem 71GP Problem A car starts rolling down a 1 -in-4 hill (1 -in-4 means that for each 4 m traveled along the sloping road, the elevation change is 1 m). How fast is it going when it reaches the bottom after traveling 55 m? (a) Ignore friction. (h) Assume an effective coefficient of friction eq

Chapter: 19 Problem: 78GP

Physics: Principles with Applications 6
(a) What minimum force is needed to lift the piano (mass ) using the pulley apparatus shown in Fig. ? (b) Determine the tension in each section of rope: \(F_{T 1}, F_{T 2}, F_{T 3}, \text { and } F_{T 4}\) Equation Transcriptio

Chapter: 19 Problem: 83GP

Physics: Principles with Applications 6
A ice skater coasts with no effort for until she stops. If the coefficient of kinetic friction between her skates and the ice is \(\mu_{k}=0.10\), how fast was she moving at the start of her coast? Equation Transcription: Text Transcription: \mu_k=0.10

Chapter: 19 Problem: 85GP

Physics: Principles with Applications 6
Problem 85GP Problem A fisherman in a boat is using a "10-lb test" fishing line. This means that the line can exert a force of 45 N without Breaking (1 lb=4.45 N). (a) How heavy a fish can the fisherman land if he pulls the fish up vertically at constant speed? (h) If he accelerates the fish upward

Chapter: 19 Problem: 2CQ

Physics: Principles with Applications 6
Problem 2CQ Problem If an object is not moving, does that mean that there are no forces acting on it? Explain.

Chapter: 19 Problem: 2PE

Physics: Principles with Applications 6
Problem 2PE An automobile has a head-on collision. A passenger in the car experiences a compression injury to the brain. Is this injury most likely to be in the front or rear portion of the brain? Explain.

Chapter: 19 Problem: 3CQ

Physics: Principles with Applications 6
Problem 3CQ An object moves in a straight line at a constant speed. Is it true that there must be no forces of any kind acting on this object? Explain.

Chapter: 19 Problem: 3P

Physics: Principles with Applications 6
Problem 3P How much tension must a rope withstand if it is used to accelerate a 960-kg car horizontally along a frictionless surface at 1.20 m/s2?

Chapter: 19 Problem: 4P

Physics: Principles with Applications 6
Problem 4P What is the weight of a 76-kg astronaut (a) on Earth, (b) on the Moon (g = 1.7 m/s2), (c) on Mars (g = 3.7 m/s2), (d) in outer space traveling with constant velocity?

Chapter: 19 Problem: 5CQ

Physics: Principles with Applications 6
Problem 5CQ If you know all of the forces acting on a moving object, can you tell in which direction the object is moving? If the answer is Yes, explain how. If the answer is No, give an example.

Chapter: 19 Problem: 5P

Physics: Principles with Applications 6
(II) A box rests on a table. ( ) What is the weight of the box and the normal force acting on it? (b) A box is placed on top of the box, as shown in Fig. . Determine the normal force that the table exerts on the box and the normal force that the box exerts on the box.

Chapter: 19 Problem: 6CQ

Physics: Principles with Applications 6
Problem 6CQ Three arrows are shot horizontally. They have left the bow and are traveling parallel to the ground as shown in Figure Q4.4 . Air resistance is negligible. Rank in order, from largest to smallest, the magnitudes of the horizontal forces acting on the arro

Chapter: 19 Problem: 6P

Physics: Principles with Applications 6
Problem 6P What average force is required to stop an 1100-kg car in 8.0 s if the car is traveling at 95 km/h?

Chapter: 19 Problem: 7CQ

Physics: Principles with Applications 6
Problem 7CQ A carpenter wishes to tighten the heavy head of his hammer onto its light handle. Which method shown in Figure Q4.5 will better tighten the head? Explain.

Chapter: 19 Problem: 7P

Physics: Principles with Applications 6
Problem 7P What average force is needed to accelerate a 7.00-gram pellet from rest to 125 m/s over a distance of 0.800 m along the barrel of a rifle?

Chapter: 19 Problem: 8CQ

Physics: Principles with Applications 6
Problem 8CQ Internal injuries in vehicular accidents may be due to what is called the third collision. The first collision is the vehicle hitting the external object. The second collision is the person hitting something on the inside of the car, such as the dashboard or windshield. This may caus

Chapter: 19 Problem: 8P

Physics: Principles with Applications 6
Problem 8P A fisherman yanks a fish vertically out of the water with an acceleration of 2.5 m/s2 using very light fishing line that has a breaking strength of 22 N. The fisherman unfortunately loses the fish as the line snaps. What can you say about the mass of the fish?

Chapter: 19 Problem: 9CQ

Physics: Principles with Applications 6
Problem 9CQ a. Give an example of the motion of an object in which the frictional force on the object is directed opposite to the motion. b. Give an example of the motion of an object in which the frictional force on the object is in the same direction as the motion.

Chapter: 19 Problem: 9P

Physics: Principles with Applications 6
Problem 9P Problem (II) A 0.140-kg baseball traveling 35.0 m/s strikes the catchers mitt, which, in bringing the ball to rest, recoils backward 11.0 cm. What was the average force applied by the ball on the glove?

Chapter: 19 Problem: 10CQ

Physics: Principles with Applications 6
Problem 10CQ Suppose you are an astronaut in deep space, far from any source of gravity. You have two objects that look identical, but one has a large mass and the other a small mass. How can you tell the difference between the two?

Chapter: 19 Problem: 10P

Physics: Principles with Applications 6
Problem 10P How much tension must a rope withstand if it is used to accelerate a 1200-kg car vertically upward at 0.80 m/s2?

Chapter: 19 Problem: 11CQ

Physics: Principles with Applications 6
Problem 11CQ Jonathan accelerates away from a stop sign. His eight-year-old daughter sits in the passenger seat. On whom does the back of the seat exert a greater force?

Chapter: 19 Problem: 11P

Physics: Principles with Applications 6
Problem 11P A particular race car can cover a quarter-mile track (402 m) in 6.40 s starting from a standstill. Assuming the acceleration is constant, how many gs does the driver experience? If the combined mass of the driver and race car is 485 kg, what horizontal force must the road exert on the t

Chapter: 19 Problem: 12CQ

Physics: Principles with Applications 6
Problem 12CQ The weight of a box sitting on the floor points directly down. The normal force of the floor on the box points directly up. Need these two forces have the same magnitude? Explain.

Chapter: 19 Problem: 58GP

Physics: Principles with Applications 6
Problem 58GP Problem describe a situation. For each problem, draw a motion diagram, a force identification diagram, and a freebody diagram. A Styrofoam ball has just been shot straight up. Air resistance is not negligible.

Chapter: 19 Problem: 59GP

Physics: Principles with Applications 6
Problem 59 GP Problem describe a situation. For each problem, draw a motion diagram, a force identification diagram, and a freebody diagram. A spring-loaded gun shoots a plastic ball. The trigger has just been pulled and the ball is starting to move down the barrel. The barrel is horizonta

Chapter: 19 Problem: 60GP

Physics: Principles with Applications 6
(III) A small block of mass m is given an initial speed \(v_{0}\) up a ramp inclined at angle \(\theta\) to the horizontal. It travels a distance d up the ramp and comes to rest. Determine a formula for the coefficient of kinetic friction between block and ramp.

Chapter: 19 Problem: 61GP

Physics: Principles with Applications 6
Problem 61 GP Problem describe a situation. For each problem, draw a motion diagram, a force identification diagram, and a freebody diagram. A gymnast has just landed on a trampoline. Shes still moving downward as the trampoline stretches.

Chapter: 19 Problem: 62GP

Physics: Principles with Applications 6
Problem 62 GP Problem describe a situation. For each problem, draw a motion diagram, a force identification diagram, and a freebody diagram. A heavy box is in the back of a truck. The truck is accelerating to the right. Apply your analysis to the box.

Chapter: 19 Problem: 63GP

Physics: Principles with Applications 6
Problem 63GP Problem describe a situation. For each problem, draw a motion diagram, a force identification diagram, and a freebody diagram. A bag of groceries is on the back seat of your car as you stop for a stop light. The bag does not slide. Apply your analysis to the bag.

Chapter: 19 Problem: 66G

Physics: Principles with Applications 6
Problem 66G The fastest pitched baseball was clocked at 46 m/s. If the pitcher exerted his force (assumed to be horizontal and constant) over a distance of 1.0 m, and a baseball has a mass of 145 g, a. Draw a free-body diagram of the ball during the pitch.

Chapter: 19 Problem: 65GP

Physics: Principles with Applications 6
Problem 65GP If a car stops suddenly, you feel thrown forward. Wed like to understand what happens to the passengers as a car stops. Imagine yourself sitting on a very slippery bench inside a car. This bench has no friction, no seat back, and theres nothing for you

Chapter: 19 Problem: 67GP

Physics: Principles with Applications 6
Problem 67GP A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than 30 gs. Calculate the force on a 70-kg person undergoing this acceleration. What distance is traveled if the person is brought to rest at this rate from 100 km/h?

Chapter: 19 Problem: 68GP

Physics: Principles with Applications 6
Problem 68GP (a) If the horizontal acceleration produced by an earthquake is a, and if an object is going to hold its place on the ground, show that the coefficient of static friction with the ground must be at least ?s = a/g. (b) The famous Loma Prieta earthquake that stopped the 1989 World Series

Chapter: 19 Problem: 69PP

Physics: Principles with Applications 6
Problem 69 PP A Simple Solution for a Stuck Car If your car is stuck in the mud and you dont have a winch to pull it out, you can use a piece of rope and a tree to do the trick. First, you tie one end of the rope to your car and the other to a tree, then pull as hard as you can on the middle

Chapter: 19 Problem: 70PP

Physics: Principles with Applications 6
Problem 70PP A Simple Solution for a Stuck Car If your car is stuck in the mud and you dont have a winch to pull it out, you can use a piece of rope and a tree to do the trick. First, you tie one end of the rope to your car and the other to a tree, then pull as

Chapter: 19 Problem: 71PP

Physics: Principles with Applications 6
Problem 71PP A Simple Solution for a Stuck Car If your car is stuck in the mud and you dont have a winch to pull it out, you can use a piece of rope and a tree to do the trick. First, you tie one end of the rope to your car and the other to a tree, then pull as hard as you can on the middle o

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