An object of mass 2 kg has a linear momentum of magnitude 6 kg . m/s. What is this object's kinetic energy? (A) 3 J (B) 6 J (C) 9 J (D) 12 J A ball of mass 0.5 kg, initially at rest, acquires a speed of 4 m/s immediately after being kicked by a force of strength 20 N. For how long did this force act on the ball? (A) 0.01 s (B) O.IS (C) 0.2 S (D) 1s A box with a mass of 2 kg accelerates in a straight line from 4 m/s to 8 m/s due to the application of a force whose duration is 0.5 s. Find the average strength of this force. (A) 4 N (B) 8 N (C) 12 N (D) 16 N A ball of mass m traveling horizontally with velocity v strikes a massive vertical wall and rebounds back along its original direction with no change in speed. What is the magnitude of the impulse delivered by the wall to the ball? (A) _mv 2 (B) mv (C) 2mv (D) 4mv. Two objects, one of mass 3 kg moving with a speed of 2 mg's and the other of mass 5 kg and speed 2 ms, move toward each other and collide headon. If the collision is perfectly inelastic, find the speed of the objects after the collision. (A) 0.25 m,-'s (B) 0.5 mfs (C) 0.75 mfs (D) 1 mg's . Object 1 moves toward Object 2, whose mass is twice that of Object 1 and which is initially at rest. After their impact, the objects lock together and move with what fraction of Object 1's initial kinetic energy? (A) 1/18 (E) 1;\"9 (C) 1! 6 (D) 1K3 . 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 (A) the collision was elastic and total linear momentum was conserved (B) the collision was elastic and total linear momentum was not conserved (C) the collision was not elastic and total linear momentum was conserved (D) the collision was not elastic and total linear momentum was not conserved . Two frictionless carts [mass = 500 g each) are sitting at rest on a perfectly level table. The teacher taps the release so that one cart pushes off the other. If one of the carts has a speed of 2 mfs, then what is the final momentum of the system [in kg - my's)? (A) 2,000 (B) 1,ooo (C) 2 (D) D Awooden block of mass M is moving at speed Vin a straight line. How fast would the bullet of mass on need to travel to stop the block (assuming that the bullet became embedded inside)? :A) mV/(m + M] :B) m V/M :C} M V/m :D) (m + MjV/W Which of the following best describes a perfectly inelastic collision free of external forces? :A) Total linear momentum is never conserved. :B) Total linear momentum is sometimes conserved. :C) Kinetic energy is never conserved. :D) Kinetic energy is always conserved. Object 1 moves with an initial speed of no toward Object 2, which has a mass half that of Object 1. If the final speed of both objects after colliding is 0, what must have been the initial speed of Object 2 (assuming no external forces)? IA) v0 :3) 2v0 :C) gun ID) 4% .A steel ball of mass m is fastened to a light cord of length L and released when the cord is horizontal. At the bottom of its path, the ball strikes a hard plastic block of mass M = 4m, initially at rest on a frictionless surface. The collision is elastic. Ia) Find the tension in the cord when the ball's height above its lowest position is 1L. 2 Write your answer in terms of m and g. :b) Find the speed of the block immediately after the collision. [c) To what height h will the ball rebound after the collision? A ballistic pendulum is a device that may be used to measure the muzzle speed of a bullet. It is composed of a wooden block suspended from a horizontal support by cords attached at each end. A bullet is shot into the block, and as a result of the perfectly inelastic impact, the block swings upward. Consider a bullet (mass m) with velocity v as it enters the block (mass M]. The length of the cords supporting the block each have length L. The maximum height to which the block swings upward after impact is denoted by y, and the maximum horizontal displacement is denoted by x. a) In terms of m, M, g, and y, determine the speed v of the bullet. b) What fraction of the bullet's original kinetic energy is lost as a result of the collision? What happens to the lost kinetic energy? c) If y is very small (so that y2 can be neglected), determine the speed of the bullet in terms of m, M, g, x, and L. :1) Once the block begins to swing, does the momentum of the block remain constant? Why or why not