# Physics exam 2.txt

 Rigid object An object with a definite shape that does not change. Axis of rotation The line of which the center of a rotating circle moves about. Radian The angle subtended by an arc whose length is equal to the radius. θ = l/r, 360 degrees = 2π rad. 1 Revolution 1 rev = 360 degrees = 2π rad. Angular displacement Δθ Angular velocity (ω). ω = θ/t Average angular velocity (ω). ω = Δθ/Δt Average angular acceleration α = lim Δω/Δt Linear and angular velocity related v = rω Frequency Number of complete revolutions per second. f = ω/2π Period T = 1/f Rolling without slipping v = rω Lever arm The distance from the axis of rotation to the line along which the force acts. Moment arm AKA lever arm. Torque (τ) The moment of the force about the axis. τ = rF Newton's 2nd law for rotation τ = I α (τ is m*N, I is kgm^2) Rotational kinetic energy Kinetic energy of a rotating object. 1/2 Iω^2 Work done by torque W = τΔθ Angular momentum L = Iω Parabolic Path A plane, flying horizontally, releases a bomb, which explodes before hitting the ground. Neglecting air resistance, the center of mass of the bomb fragments, just after the explosion moves along a ___ In a game of pool, the white cue ball hits the #5 ball and stops while the #5 ball moves away with the same velocity as the cue ball had originally. The type of collision is ___ elastic Magnitude Impulse Two equal mass balls, A and B, are dropped from the same height, and rebound off the floor. The A ball rebounds to a higher position. The A ball is subjected to the greater ___ during its collision with the floorMomentum (Kinetic Energy) The product of an object's mass and velocity is equal to ___ External Forces Kinetic energy is never conserved for a perfectly inelastic collision free of ___ Center of Mass Tightrope walkers walk with a long flexible rod in order to lower their __ Momentum Change A small object collides with a large object and sticks. Both objects experience the same magnitude of ___ Some Point For an object on the surface of the earth, the center gravity and the center of mass are the ___ Conserved Two objects move toward each other collide, and separate. If there was no net external force acting on the objects, but some kinetic energy was lost, then the collision was not elastic and total linear momentum was ___ the same In a baseball game, a batter hits a ball for a home run. Compared to the magnitude of the impulse imparted to the ball, the magnitude of the impulse imparted to the bat is ___ Momentum A rubber ball and a lump of putty have equal mass. They are thrown with equal speed against a wall. the ball bounces back with nearly the same speed with which it hit. the putty sticks to the wall. The ball experiences the greater ___ Elastic Kinetic energy is conserved when it is an __ collision. the time of impact A baseball catcher wears a glove rather than just using bare hands to catch a pitched baseball because the force on the catcher's hand is reduced because the glove increases __ Conserved two objects collide and stick together. Kinetic energy is definitely not ___ Decreases A freight car moves along a frictionless level railroad Elastic two objects collide and bounce off each other. Kinetic energy is conserved only if the collision is ___ They are the Same A golf ball moving east at a speed of 4 m/s, collides with a stationary bowling ball. The golf ball bounces back to west, and the bowling ball moves very slowly to the east. Neither other experiences the greater magnitude impulse ___ Conserved Two objects collide and stick together. Linear momentum is definitely __ Constant If an object is acted on by a non-zero net external force, its momentum will not remain ___ Conserved When a cannon fires a cannonball, the cannon will recoil backward because the momentum of the cannonball and the cannon is __"Balance Point" The center of gravity of an object may be thought of as the __ Backwards A 100-kg football linebacker moving at 2 m/s tackles head-on an 80-kg halfback running 3 m/s. Neglecting the effects due to digging in of cleats, the halfback will drive the linebacker __ Impulse The area under the curve on an F-t graph represents __ Conserved When two cars collide and lock together both momentum and total energy is __ Same Average Force A small car meshes with a large truck in a head-on collision. The small car and large truck experience the __ Vector Momentum is a __ quantity Acceleration Due to Gravity The graph below shows the relationship between weight and mass for a series of objects, the slope of the graph represents __ Doubled If the mass of a moving object could be doubled, the inertia would be __ 4x as great compared to the inertia of a 1-kg mass, the inertia of a 4kg mass would be __ weight and momentum a copper coin is resting on a piece of cardboard is placed on a beaker as shown in the diagram below when the cardboard is rapidly removed, the coin drops into the beaker. The properties of the coin which best explain its fall are its __ Decrease As the mass of an object decreases, its inertia will __ greater momentum A 5N ball and a 10N ball are released simultaneously from a point 50m above the surface of the Earth. Neglecting air resistance, which statement is true? at the end of 3s of free-fall. the 10 N ball will have a ______ than the 5N ball. More Momentum In the diagram below, a .4kg steel sphere and a .1kg wooden sphere are located 2.0m above the ground. Both spheres are allowed to fall from rest. Best statement when they fell 1m: Both spheres have the same sped and the steel sphere has _______ then the wooden sphere. Uniform Circular Motion Movement in a circle at a constant velocity, v. Acceleration Equation A = (change in velocity)/(change in time) Centripetal Acceleration/Radial Acceleration Acceleration towards the center of a circle (Centripetal = "center-pointing") Centripetal Acceleration Equation A = v²/r Frequency The number of revolutions per second. Defined as f. Period Time required to complete one revolution. Defined as T. Equation Relating Frequency and Period T = 1/f Centripetal Force equation F = mv²/r Law of Universal Gravitation Every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This force acts along the line joining the two particles. Law of Universal Gravitation Equation F = G(m1m2)/r² Value of the constant G G = 6.67 x 10⁻¹¹ Nm²/kg² Velocity of an object in uniform circular motion v = (2pir)/T Kepler's First Law of Planetary Motion The path of each planet about the Sun is an ellipse with the Sun at one focus Kepler's Second Law of Planetary Motion Each planet moves so that an imaginary line drawn from the Sun to the planet sweeps out equal areas in equal periods of time Kepler's Third Law of Planetary Motion The ratio of the squares of the periods T of any two planets revolving about the sun is equal to the ratio of the cubes of their mean distances s from the sun. (T1/T2)² = (s1/s2)² Perturbations Deviations; perturbations in planetary orbits helped Newton formulate the law of universal gravitation Causal Laws Laws formulated by Newton Causality The idea that one occurrence can cause another Kepler's Laws of Planetary Motion A detailed description of the motion of planets about the Sun, written by Johannes Kepler Gravitational force equation Force of gravity is inversely proportional to the square of the distance r from the Earth's center (Force of Gravity = 1/r²EnergyThe ability to do work. Work W = F * d. Measured in joules. Joule 1 J = 1 N * m Kinetic energy KE = 1/2 m * v^2 Net work Wsubnet = ΔKE Work-energy principle The net work done on an object is equal to the change in the object's kinetic energy. Potential energy PE = m g h Gravitational potential energy PEsubgravity = m g y Spring equation Fsubs = -k * x Hooke's law AKA spring equation Elastic potential energy Elastic PE = 1/2 k * x^2 Conservative forces Forces which the work does not depend on the path taken rather then the initial and final positions. Eg: gravity. Nonconservative forces Forces that its work depends on the path. Eg: friction. Total mechanical energy Esub2 = Esub1 Conserved quantity Law of conservation, Esub2 = Esub1, KE + PE = KE + PE Principle of conservation of mechanical energy If only conservative forces are acting, the total mechanical energy of a system neither increases nor decreases in any process. It is conserved. Law of conservation of energy The total energy is neither increased nor decreased in any process. Energy can be transformed from one form to another, and transferred from one object to another, but the total amount remains constant. Dissipative forces Forces that dissipate mechanical energy rather then the total energy. Power P = work/time. Measured in Watts Watt 1 W = 1 J/s AuthorAnonymous ID299355 Card SetPhysics exam 2.txt DescriptionPhysics1 exam 2 Updated2015-03-28T14:18:45Z Show Answers