Physics for Scientists and Engineers, Volume 1, Technology Update 9th Edition solutions

Physics for Scientists and Engineers, Volume 1, Technology Update 9
You hold a slingshot at arms length, pull the light elastic band back to your chin, and release it to launch a pebble horizontally with speed 200 cm/s. With the same procedure, you fire a bean with speed 600 cm/s. What is the ratio of the mass of the bean to the mass of the pebble? (a) 19 (b) 13 (c)

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Two children stand on a platform at the top of a curving slide next to a backyard swimming pool. At the same moment the smaller child hops off to jump straight down into the pool, the bigger child releases herself at the top of the frictionless slide. (i) Upon reaching the water, the kinetic energy o

Physics for Scientists and Engineers, Volume 1, Technology Update 9
At the bottom of an air track tilted at angle u, a glider of mass m is given a push to make it coast a distance d up the slope as it slows down and stops. Then the glider comes back down the track to its starting point. Now the experiment is repeated with the same original speed but with a second ide

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An athlete jumping vertically on a trampoline leaves the surface with a velocity of 8.5 m/s upward. What maximum height does she reach? (a) 13 m (b) 2.3 m (c) 3.7 m (d) 0.27 m (e) The answer cant be determined because the mass of the athlete isnt given.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Answer yes or no to each of the following questions. (a) Can an objectEarth system have kinetic energy and not gravitational potential energy? (b) Can it have gravitational potential energy and not kinetic energy? (c) Can it have both types of energy at the same moment? (d) Can it have neither?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
In a laboratory model of cars skidding to a stop, data are measured for four trials using two blocks. The blocks have identical masses but different coefficients of kinetic friction with a table: mk 5 0.2 and 0.8. Each block is launched with speed vi 5 1 m/s and slides across the level table as the b

Physics for Scientists and Engineers, Volume 1, Technology Update 9
What average power is generated by a 70.0-kg mountain climber who climbs a summit of height 325 m in 95.0 min? (a) 39.1 W (b) 54.6 W (c) 25.5 W (d) 67.0 W (e) 88.4 W

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A ball of clay falls freely to the hard floor. It does not bounce noticeably, and it very quickly comes to rest. What, then, has happened to the energy the ball had while it was falling? (a) It has been used up in producing the downward motion. (b) It has been transformed back into potential energy.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A pile driver drives posts into the ground by repeatedly dropping a heavy object on them. Assume the object is dropped from the same height each time. By what factor does the energy of the pile driverEarth system change when the mass of the object being dropped is doubled? (a) 12 (b) 1; the energy is

Physics for Scientists and Engineers, Volume 1, Technology Update 9
In Chapter 7, the workkinetic energy theorem, W 5 DK, was introduced. This equation states that work done on a system appears as a change in kinetic energy. It is a special-case equation, valid if there are no changes in any other type of energy such as potential or internal. Give two or three exampl

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. The system shown in Figure P8.11 consists of a light, inextensible cord, light, frictionless pulleys, and blocks of equal mass. Notice that block B is attached to one of the pulleys. The system is initially held at rest so that the blocks are at the same height above the ground. The blocks ar

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A sled of mass m is given a kick on a frozen pond. The kick imparts to the sled an initial speed of 2.00 m/s. The coefficient of kinetic friction between sled and ice is 0.100. Use energy considerations to find the distance the sled moves before it stops.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A sled of mass m is given a kick on a frozen pond. The kick imparts to the sled an initial speed of v. The coefficient of kinetic friction between sled and ice is mk. Use energy considerations to find the distance the sled moves before it stops.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A crate of mass 10.0 kg is pulled up a rough incline with an initial speed of 1.50 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20.08 with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.00 m. (a) How much work is done by the

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A block of mass m 5 2.00 kg is attached to a spring of force constant k 5 500 N/m as shown in Figure P8.15. The block is pulled to a position xi 5 5.00 cm to the right of equilibrium and released from rest. Find the speed the block has as it passes through equilibrium if (a) the horizontal surface is

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 40.0-kg box initially at rest is pushed 5.00 m along a rough, horizontal floor with a constant applied horizontal force of 130 N. The coefficient of friction between box and floor is 0.300. Find (a) the work done by the applied force, (b) the increase in internal energy in the boxfloor system as a

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A smooth circular hoop with a radius of 0.500 m is placed flat on the floor. A 0.400-kg particle slides around the inside edge of the hoop. The particle is given an initial speed of 8.00 m/s. After one revolution, its speed has dropped to 6.00 m/s because of friction with the floor. (a) Find the ener

Physics for Scientists and Engineers, Volume 1, Technology Update 9
At time ti, the kinetic energy of a particle is 30.0 J and the potential energy of the system to which it belongs is 10.0 J. At some later time tf , the kinetic energy of the particle is 18.0 J. (a) If only conservative forces act on the particle, what are the potential energy and the total energy of

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A boy in a wheelchair (total mass 47.0 kg) has speed 1.40 m/s at the crest of a slope 2.60 m high and 12.4 m long. At the bottom of the slope his speed is 6.20 m/s. Assume air resistance and rolling resistance can be modeled as a constant friction force of 41.0 N. Find the work he did in pushing forw

Physics for Scientists and Engineers, Volume 1, Technology Update 9
As shown in Figure P8.20, a green bead of mass 25 g slides along a straight wire. The length of the wire from point A to point B is 0.600 m, and point A is 0.200 m higher than point B. A constant friction force of magnitude 0.025 0 N acts on the bead. (a) If the bead is released from rest at point A,

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A toy cannon uses a spring to project a 5.30-g soft rubber ball. The spring is originally compressed by 5.00 cm and has a force constant of 8.00 N/m. When the cannon is fired, the ball moves 15.0 cm through the horizontal barrel of the cannon, and the barrel exerts a constant friction force of 0.032

Physics for Scientists and Engineers, Volume 1, Technology Update 9
The coefficient of friction between the block of mass m1 5 3.00 kg and the surface in Figure P8.22 is mk 5 0.400. The system starts from rest. What is the speed of the ball of mass m2 5 5.00 kg when it has fallen a distance h 5 1.50 m?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 5.00-kg block is set into motion up an inclined plane with an initial speed of vi 5 8.00 m/s (Fig. P8.23). The block comes to rest after traveling d 5 3.00 m along the plane, which is inclined at an angle of u 5 30.08 to the horizontal. For this motion, determine (a) the change in the blocks kineti

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 1.50-kg object is held 1.20 m above a relaxed massless, vertical spring with a force constant of 320 N/m. The object is dropped onto the spring. (a) How far does the object compress the spring? (b) What If? Repeat part (a), but this time assume a constant air-resistance force of 0.700 N acts on the

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 200-g block is pressed against a spring of force constant 1.40 kN/m until the block compresses the spring 10.0 cm. The spring rests at the bottom of a ramp inclined at 60.08 to the horizontal. Using energy considerations, determine how far up the incline the block moves from its initial position be

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An 80.0-kg skydiver jumps out of a balloon at an altitude of 1 000 m and opens his parachute at an altitude of 200 m. (a) Assuming the total retarding force on the skydiver is constant at 50.0 N with the parachute closed and constant at 3 600 N with the parachute open, find the speed of the skydiver

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A child of mass m starts from rest and slides without friction from a height h along a slide next to a pool (Fig. P8.27). She is launched from a height h/5 into the air over the pool. We wish to find the maximum height she reaches above the water in her projectile motion. (a) Is the childEarth system

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Sewage at a certain pumping station is raised vertically by 5.49 m at the rate of 1 890 000 liters each day. The sewage, of density 1 050 kg/m3, enters and leaves the pump at atmospheric pressure and through pipes of equal diameter. (a) Find the output mechanical power of the lift station. (b) Assume

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An 820-N Marine in basic training climbs a 12.0-m vertical rope at a constant speed in 8.00 s. What is his power output?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
The electric motor of a model train accelerates the train from rest to 0.620 m/s in 21.0 ms. The total mass of the train is 875 g. (a) Find the minimum power delivered to the train by electrical transmission from the metal rails during the acceleration. (b) Why is it the minimum power?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
When an automobile moves with constant speed down a highway, most of the power developed by the engine is used to compensate for the energy transformations due to friction forces exerted on the car by the air and the road. If the power developed by an engine is 175 hp, estimate the total friction for

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A certain rain cloud at an altitude of 1.75 km contains 3.20 3 107 kg of water vapor. How long would it take a 2.70-kW pump to raise the same amount of water from the Earths surface to the clouds position?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An energy-efficient lightbulb, taking in 28.0 W of power, can produce the same level of brightness as a conventional lightbulb operating at power 100 W. The lifetime of the energy-efficient bulb is 10 000 h and its purchase price is $4.50, whereas the conventional bulb has a lifetime of 750 h and cos

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An electric scooter has a battery capable of supplying 120 Wh of energy. If friction forces and other losses account for 60.0% of the energy usage, what altitude change can a rider achieve when driving in hilly terrain if the rider and scooter have a combined weight of 890 N?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Make an order-of-magnitude estimate of the power a car engine contributes to speeding the car up to highway speed. In your solution, state the physical quantities you take as data and the values you measure or estimate for them. The mass of a vehicle is often given in the owners manual.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An older-model car accelerates from 0 to speed v in a time interval of Dt. A newer, more powerful sports car accelerates from 0 to 2v in the same time period. Assuming the energy coming from the engine appears only as kinetic energy of the cars, compare the power of the two cars.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 10.0 mi/h, a cyclist uses food energy at a rate of about 400 kcal/h above what he would use if merely sitting still. (In exercise physiology, power is ofte

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 650-kg elevator starts from rest. It moves upward for 3.00 s with constant acceleration until it reaches its cruising speed of 1.75 m/s. (a) What is the average power of the elevator motor during this time interval? (b) How does this power compare with the motor power when the elevator moves at its

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 3.50-kN piano is lifted by three workers at constant speed to an apartment 25.0 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 165 W of power, and the pulley system is 75.0% efficient (so that 25.0% of the mechanical energy is transform

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kcal 5 4 186 J. Metabolizing 1 g of fat can release 9.00 kcal. A student decides to try to lose weight by exercising. He plans to run up and down the stairs in a football stad

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 30.08 above the horizontal. The car accelerates uniformly to a speed of 2.20 m/s in 12.0 s and then continues

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Make an order-of-magnitude estimate of your power output as you climb stairs. In your solution, state the physical quantities you take as data and the values you measure or estimate for them. Do you consider your peak power or your sustainable power?

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A small block of mass m 5 200 g is released from rest at point A along the horizontal diameter on the inside of a frictionless, hemispherical bowl of radius R 5 30.0 cm (Fig. P8.43). Calculate (a) the gravitational potential energy of the blockEarth system when the block is at point A relative to poi

Physics for Scientists and Engineers, Volume 1, Technology Update 9
What If? The block of mass m 5 200 g described in Problem 43 (Fig. P8.43) is released from rest at point A, and the surface of the bowl is rough. The blocks speed at point B is 1.50 m/s. (a) What is its kinetic energy at point B? (b) How much mechanical energy is transformed into internal energy as t

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. A boy starts at rest and slides down a frictionless slide as in Figure P8.45. The bottom of the track is a height h above the ground. The boy then leaves the track horizontally, striking the ground at a distance d as shown. Using energy methods, determine the initial height H of the boy above

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. As shown in Figure P8.46, a light string that does not stretch changes from horizontal to vertical as it passes over the edge of a table. The string connects m1, a 3.50-kg block originally at rest on the horizontal table at a height h 5 1.20 m above the floor, to m2, a hanging 1.90-kg block o

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 4.00-kg particle moves along the x axis. Its position varies with time according to x 5 t 1 2.0t 3, where x is in meters and t is in seconds. Find (a) the kinetic energy of the particle at any time t, (b) the acceleration of the particle and the force acting on it at time t, (c) the power being del

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Why is the following situation impossible? A softball pitcher has a strange technique: she begins with her hand at rest at the highest point she can reach and then quickly rotates her arm backward so that the ball moves through a half-circle path. She releases the ball when her hand reaches the botto

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A skateboarder with his board can be modeled as a particle of mass 76.0 kg, located at his center of mass (which we will study in Chapter 9). As shown in Figure P8.49, the skateboarder starts from rest in a crouching position at one lip of a half-pipe (point A). The half-pipe is one half of a cylinde

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Heedless of danger, a child leaps onto a pile of old mattresses to use them as a trampoline. His motion between two particular points is described by the energy conservation equation 12 146.0 kg2 12.40 m/s 22 1 146.0 kg2 19.80 m/s2 2 12.80 m 1 x2 5 1211.94 3 104 N/m2x2 (a) Solve the equation for x. (

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Jonathan is riding a bicycle and encounters a hill of height 7.30 m. At the base of the hill, he is traveling at 6.00 m/s. When he reaches the top of the hill, he is traveling at 1.00 m/s. Jonathan and his bicycle together have a mass of 85.0 kg. Ignore friction in the bicycle mechanism and between t

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Jonathan is riding a bicycle and encounters a hill of height h. At the base of the hill, he is traveling at a speed vi. When he reaches the top of the hill, he is traveling at a speed vf . Jonathan and his bicycle together have a mass m. Ignore friction in the bicycle mechanism and between the bicycl

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Consider the blockspringsurface system in part (B) of Example 8.6. (a) Using an energy approach, find the position x of the block at which its speed is a maximum. (b) In the What If? section of this example, we explored the effects of an increased friction force of 10.0 N. At what position of the blo

Physics for Scientists and Engineers, Volume 1, Technology Update 9
As it plows a parking lot, a snowplow pushes an evergrowing pile of snow in front of it. Suppose a car moving through the air is similarly modeled as a cylinder of area A pushing a growing disk of air in front of it. The originally stationary air is set into motion at the constant speed v of the cyli

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A wind turbine on a wind farm turns in response to a force of high-speed air resistance, R 5 12 DrAv2. The power available is P 5 Rv 5 12 Drpr 2v3, where v is the wind speed and we have assumed a circular face for the wind turbine of radius r. Take the drag coefficient as D 5 1.00 and the density of

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Consider the popgun in Example 8.3. Suppose the projectile mass, compression distance, and spring constant remain the same as given or calculated in the example. Suppose, however, there is a friction force of magnitude 2.00 N acting on the projectile as it rubs against the interior of the barrel. The

Physics for Scientists and Engineers, Volume 1, Technology Update 9
As the driver steps on the gas pedal, a car of mass 1 160 kg accelerates from rest. During the first few seconds of motion, the cars acceleration increases with time according to the expression a 5 1.16t 2 0.210t 2 1 0.240t 3 where t is in seconds and a is in m/s2. (a) What is the change in kinetic e

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. Why is the following situation impossible? A new high-speed roller coaster is claimed to be so safe that the passengers do not need to wear seat belts or any other restraining device. The coaster is designed with a vertical circular section over which the coaster travels on the inside of the

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A horizontal spring attached to a wall has a force constant of k 5 850 N/m. A block of mass m 5 1.00 kg is attached to the spring and rests on a frictionless, horizontal surface as in Figure P8.59. (a) The block is pulled to a position xi 5 6.00 cm from equilibrium and released. Find the elastic pote

Physics for Scientists and Engineers, Volume 1, Technology Update 9
More than 2 300 years ago, the Greek teacher Aristotle wrote the first book called Physics. Put into more precise terminology, this passage is from the end of its Section Eta: Let P be the power of an agent causing motion; w, the load moved; d, the distance covered; and Dt, the time interval required

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A childs pogo stick (Fig. P8.61) stores energy in a spring with a force constant of 2.50 3 104 N/m. At position A (xA 5 20.100 m), the spring compression is a maximum and the child is momentarily at rest. At position B (xB 5 0), the spring is relaxed and the child is moving upward. At position C, the

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 1.00-kg object slides to the right on a surface having a coefficient of kinetic friction 0.250 (Fig. P8.62a). The object has a speed of vi 5 3.00 m/s when it makes contact with a light spring (Fig. P8.62b) that has a force constant of 50.0 N/m. The object comes to rest after the spring has been com

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A 10.0-kg block is released from rest at point A in Figure P8.63. The track is frictionless except for the portion between points B and C, which has a length of 6.00 m. The block travels down the track, hits a spring of force constant 2 250 N/m, and compresses the spring 0.300 m from its equilibrium

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A block of mass m1 5 20.0 kg is connected to a block of mass m2 5 30.0 kg by a massless string that passes over a light, frictionless pulley. The 30.0-kg block is connected to a spring that has negligible mass and a force constant of k 5 250 N/m as shown in Figure P8.64. The spring is unstretched whe

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A block of mass 0.500 kg is pushed against a horizontal spring of negligible mass until the spring is compressed a distance x (Fig. P8.65). The force constant of the spring is 450 N/m. When it is released, the block travels along a frictionless, horizontal surface to point A, the bottom of a vertical

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. As a prank, someone has balanced a pumpkin at the highest point of a grain silo. The silo is topped with a hemispherical cap that is frictionless when wet. The line from the center of curvature of the cap to the pumpkin makes an angle ui 5 08 with the vertical. While you happen to be standin

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. The mass of a car is 1 500 kg. The shape of the cars body is such that its aerodynamic drag coefficient is D 5 0.330 and its frontal area is 2.50 m2. Assuming the drag force is proportional to v2 and ignoring other sources of friction, calculate the power required to maintain a speed of 100 k

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A pendulum, comprising a light string of length L and a small sphere, swings in the vertical plane. The string hits a peg located a distance d below the point of suspension (Fig. P8.68). (a) Show that if the sphere is released from a height below that of the peg, it will return to this height after t

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A block of mass M rests on a table. It is fastened to the lower end of a light, vertical spring. The upper end of the spring is fastened to a block of mass m. The upper block is pushed down by an additional force 3mg, so the spring compression is 4mg/k. In this configuration, the upper block is relea

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. Why is the following situation impossible? An athlete tests her hand strength by having an assistant hang weights from her belt as she hangs onto a horizontal bar with her hands. When the weights hanging on her belt have increased to 80% of her body weight, her hands can no longer support her

Physics for Scientists and Engineers, Volume 1, Technology Update 9
While running, a person transforms about 0.600 J of chemical energy to mechanical energy per step per kilogram of body mass. If a 60.0-kg runner transforms energy at a rate of 70.0 W during a race, how fast is the person running? Assume that a running step is 1.50 m long.

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A roller-coaster car shown in Figure P8.72 is released from rest from a height h and then moves freely with negligible friction. The roller-coaster track includes a circular loop of radius R in a vertical plane. (a) First suppose the car barely makes it around the loop; at the top of the loop, the ri

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A ball whirls around in a vertical circle at the end of a string. The other end of the string is fixed at the center of the circle. Assuming the total energy of the ball Earth system remains constant, show that the tension in the string at the bottom is greater than the tension at the top by six time

Physics for Scientists and Engineers, Volume 1, Technology Update 9
An airplane of mass 1.50 3 104 kg is in level flight, initially moving at 60.0 m/s. The resistive force exerted by air on the airplane has a magnitude of 4.0 3 104 N. By Newtons third law, if the engines exert a force on the exhaust gases to expel them out of the back of the engine, the exhaust gases

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Consider the blockspring collision discussed in Example 8.8. (a) For the situation in part (B), in which the surface exerts a friction force on the block, show that the block never arrives back at x 5 0. (b) What is BIO S S Q/C Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied,

Physics for Scientists and Engineers, Volume 1, Technology Update 9
In bicycling for aerobic exercise, a woman wants her heart rate to be between 136 and 166 beats per minute. Assume that her heart rate is directly proportional to her mechanical power output within the range relevant here. Ignore all forces on the womanbicycle system except for static friction forwar

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. In 1887 in Bridgeport, Connecticut, C. J. Belknap built the water slide shown in Figure P8.77. A rider on a small sled, of total mass 80.0 kg, pushed off to start at the top of the slide (point A) with a speed of 2.50 m/s. The chute was 9.76 m high at the top and 54.3 m long. Along its length

Physics for Scientists and Engineers, Volume 1, Technology Update 9
In a needle biopsy, a narrow strip of tissue is extracted from a patient using a hollow needle. Rather than being pushed by hand, to ensure a clean cut the needle can be fired into the patients body by a spring. Assume that the needle has mass 5.60 g, the light spring has force constant 375 N/m, and

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Review. A uniform board of length L is sliding along a smooth, frictionless, horizontal plane as shown in Figure P8.79a. The board then slides across the boundary with a rough horizontal surface. The coefficient of kinetic friction between the board and the second surface is mk. (a) Find the accelera

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Starting from rest, a 64.0-kg person bungee jumps from a tethered hot-air balloon 65.0 m above the ground. The bungee cord has negligible mass and unstretched length 25.8 m. One end is tied to the basket of the balloon and the other end to a harness around the persons body. The cord is modeled as a s

Physics for Scientists and Engineers, Volume 1, Technology Update 9
Jane, whose mass is 50.0 kg, needs to swing across a river (having width D) filled with person-eating crocodiles to save Tarzan from danger. She must swing into a wind exerting constant horizontal force F S , on a vine having length L and initially making an angle u with the vertical (Fig. P8.81). Ta

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A ball of mass m 5 300 g is connected by a strong string of length L 5 80.0 cm to a pivot and held in place with the string vertical. A wind exerts constant force F to the right on the ball as shown in Figure P8.82. The ball is released from rest. The wind makes it swing up to attain maximum height H

Physics for Scientists and Engineers, Volume 1, Technology Update 9
What If? Consider the roller coaster described in Problem 58. Because of some friction between the coaster and the track, the coaster enters the circular section at a speed of 15.0 m/s rather than the 22.0 m/s in Problem 58. Is this situation more or less dangerous for the passengers than that in Pro

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A uniform chain of length 8.00 m initially lies stretched out on a horizontal table. (a) Assuming the coefficient of static friction between chain and table is 0.600, show that the chain will begin to slide off the table if at least 3.00 m of it hangs over the edge of the table. (b) Determine the spe

Physics for Scientists and Engineers, Volume 1, Technology Update 9
A daredevil plans to bungee jump from a balloon 65.0 m above the ground. He will use a uniform elastic cord, tied to a harness around his body, to stop his fall at a point 10.0 m above the ground. Model his body as a particle and the cord as having negligible mass and obeying Hookes law. In a prelimi