General Physics 151 Week 3 Notes (September 12, 2016)
General Physics 151 Week 3 Notes (September 12, 2016) PHYS151
Popular in General Physics I
verified elite notetaker
Popular in Physics
This 4 page Class Notes was uploaded by Lindsey Notetaker on Monday September 19, 2016. The Class Notes belongs to PHYS151 at University of Nevada - Las Vegas taught by Dr. Pang in Fall 2016. Since its upload, it has received 31 views. For similar materials see General Physics I in Physics at University of Nevada - Las Vegas.
Reviews for General Physics 151 Week 3 Notes (September 12, 2016)
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/19/16
General Physics 151 Week 3 Notes (September 12, 2016) Chapter 3: Forces and Motion Change Key to my notes: all notes that are taken from the lecture will be the first section, notes I take from the textbook will be the second section, and the vocabulary words from the chapter with definitions will be the last sections! (: Lecture Notes Forcea measure of action that causes an object to change its current state o It is a vector measured in Newtons (N) o Can alter the equilibrium of an object Statephysical characteristics of an object to remain its current state Massmeasure of inertia o Inertiathe tendency of an object to remain its current state o Measured in kilograms (kg) o Higher mass means the more difficult it is to move Accelerationthe rate of velocity change o Measured in meters per seconds squared Newton’s first law every body continues in its state or rest, or of uniform motion in a right line, unless it is compelled to change that state by a force impressed on it o Modern: an object remains in its current state, at rest or moving with a constant velocity, unless acted upon by a nonzero net force Look at things as a point so start with an object and then have it become a point and multiple points become a system Newton’s second law (equation of motion)change of motion is proportional to the motive force impressed; and it made in the direction of the right line in which force is impressed o Modern: the acceleration of an object is proportional to the net force exerted on it and to the inverse of the mass o Acceleration = (total net force exerted on the object)/(mass of the object) o Force= (Acceleration of the object) X (mass of the object) Measured in (kilograms X meters)/(seconds squared) o Negative force is when it is moving away from the object Problem solving techniques o Draw all the forces on each object o Choose a convenient coordinate system o Decompose all the forces along perpendicular directions o Apply Newton’s second law along each axis Newton’s third law says that for every action there is an opposite and equal reaction o F12=F21 Gravity is also known as universal gravitational force o Fundamental forces Page 1 of 4 General Physics 151 Week 3 Notes (September 12, 2016) Gravity On earth it is a constant of about 9.80 meters per seconds squared It is known as weight on earth so weight = mass X gravity Electroweak force Strong force Practical forces o Gravity (weight) o Contact force Normal forcethe normal component of the constant force Frictionalways against the relative motion The tangential component (along the interface) of the contact force between two objects in contact o Stress Elastic force Tension Pressure o Viscosity Textbook Notes Even big objects can be looked at as a point o represents an object well if the length scale of its motion is much greater than its size or every point on the object behaves You take an object and then turn it into a point and from there it can be turned into a system which is a collection of points Having a reference point allows to see the motion that was caused by the force generally believed that the great insight of Galileo on the motion of freefalling objects was the main drive that led Newton to discover his laws of motion Newton’s second law is also known as the “equation of motion” o Force = mass X acceleration Problemsolving strategies—Freebody diagram approach: o Draw all the forces on each of the objects correctly; o Choose a convenient coordinate system; o Decompose all the forces along perpendicular directions (axes); o Apply Newton’s second law (equation of motion) along each of the three directions if necessary; o Make connection to the kinematics of the object through its acceleration. There are three types of fundamental forces o Gravity Page 2 of 4 General Physics 151 Week 3 Notes (September 12, 2016) exists between any two objects that have masses and it was formulated mathematically by Newton F = −G[(mass of object 1 X mass of object 2)/( distance of separation of the two particles) G = 6.67384(80) ×10−11 m3/(kgs2) Gravity equals 9.80 meters per seconds squared Does not need to be in contact to experience o Electroweak forces exists between charged particles and elementary particles o Strong force responsible for keeping nucleons together in a nucleus weight = mass X gravity Weak force and strong force act at the subatomic scale and usually require special equipments in order to see them in action There are two types of frictions o Static friction is the resistive force resulted from the tendency of relative motion of the two objects in contact, but not actually having a relative motion o kinetic friction is the resistive force resulted from the actual relative motion of the two objects in contact too much tension can cause objects to snap or break Vocabulary Words Dynamics: the way in which objects of an interacting system behave, react, and aﬀect each other State: an object’s physical characteristics at the given moment, such as its velocity, geometric shape, and content distribution Mass: is a measure of its inertia Force: a measure of an action that causes an object to change its current state of motion; it is the means of delivering interaction Newton’s First Law: an object remains in its current state, at rest or moving with a constant velocity, unless acted upon by a nonzero net force Newton’s Second Law: The acceleration of an object is proportional to the net force exerted on it and to the inverse of its mass FreeBody Diagram: with each of the objects involved isolated from one another by replacing each interaction with a force sketched as a vector on the object Page 3 of 4 General Physics 151 Week 3 Notes (September 12, 2016) Newton’s Third Law: The action on one object is equal in magnitude but opposite in direction to the reaction on the other for two objects in interaction. Weight: a measure the gravity on an object near the surface of Earth Normal Force: is the component of the contact force normal or perpendicular to the interface Friction: is the tangential component of the contact force between the two objects Static Friction: is the resistive force resulted from the tendency of relative motion of the two objects in contact, but not actually having a relative motion Kinetic Friction: is the resistive force resulted from the actual relative motion of the two objects in contact Tension: the state of being stretched tight. Equilibrium: when net forces equal zero Page 4 of 4
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'