Momentum And Collisions - Conceptual Questions

In the figure, determine the character of the collision. The masses of the blocks before and after are shown. The collision is Before: 4 kg @ 1.8 m/s => + 6 kg @ 0.2 m/s <= After: 4 kg @ 0.6 m/s <= + 6 kg @ 1.4 m/s => A) Perfectly Elastic B) Partially inelastic C) Completely Inelastic D) Characterized by an increase in kinetic energy. E) not possible because momentum is not conserved

A) Perfectly Elastic Pi = Pf KEi = KEf

A firecracker explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion: I. The total momentum of the fragments is equal to the original momentum of the firecracker. II. The total kinetic energy of the fragments is equal to the original kinetic energy of the firecracker. A) Statement I only B) Statement II only C) Both Statement I and Statement II D) Neither statement is true

A) Statement I only

Two objects of different masses have equal, non-zero kinetic energies. Which object has the greater magnitude momentum? A) The heavier object B) The lighter object C) They both have the same magnitude momentum

A) The heavier object

A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true? (There could be more than one correct choice.) A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball. B) The magnitude of the change of velocity the 5-kg ball experiences is less than that of the 10-kg ball. C) The magnitude of the change of velocity the 5-kg ball experiences is equal to that of the 10-kg ball. D) The magnitude of the change of velocity the 5-kg ball experiences is equal to the magnitude of the change of momentum of the 10-kg ball. E) Both balls lose all their momentum since the collision is inelastic

A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball. D) The magnitude of the change of velocity the 5-kg ball experiences is equal to the magnitude of the change of momentum of the 10-kg ball.

Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum? A) They all have the same amount of momentum. B) Car X C) Car Y D) Car Z

A) They all have the same amount of momentum Change in Momentum = I Change in Momentum = Ft

A rubber ball and a lump of clay 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 clay sticks to the wall. Which one of these objects experiences the greater momentum change? A) the ball B) the clay C) Both of them experience the same non-zero momentum change D) Both of them experience zero momentum change

A) the ball (greater change in Velocity => Greater momentum)

A rubber ball bounces off of a wall with an initial speed v and reverses its direction so its speed is v right after the bounce. As a result of this bounce, which of the following quantities of the ball are conserved? (There could be more than one correct choice.) A) The kinetic energy of the ball B) The momentum of the ball C) both the momentum and the kinetic energy of the ball D) None of the above quantities are conserved

A) the kinetic energy of the ball

If you want to double the kinetic energy of a gas molecule, by what factor must you increase its momentum? A) √2 B) 2 C) 2√2 D) 4 E) 16

A) √2

Two objects of different masses have momentum of equal, non-zero magnitude. Which object has more kinetic energy? A) The heavier object B) The lighter object C) They both have the same kinetic energy

B) The lighter object

A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is A) 25 times as great as the momentum change of the heavier fragment. B) The same as the momentum change of the heavier fragment. C) 1/25 as great as the momentum change of the heavier fragment. D) 5 times as great as the momentum change of the heavier fragment. E) 1/4 as great as the momentum change of the heavier fragment.

B) The same as the momentum change of the heavier fragment

A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system A) is the same as before. B) is half as much as before. C) is one third as much as before. D) is one fourth as much as before E) is one quarter as much as before

B) is half as much as before.

A 2.0-kg ball moving eastward at 3.0 m/s suddenly collides with and sticks to a 4.0-kg ball moving northward at 2.0 m/s. What is the magnitude of the momentum of this system just after the collision? A) 14 kg*m/s B) 2.0 kg*m/s C) 10 kg*m/s D) 6.0 kg*m/s E) 8.0 kg*m/s

C) 10 kg*m/s (2.0 kg * 3.0 m/s) = 6.0 kg*m/s = a (4.0 kg * 2.0 m/s) = 8.0 kg*m/s = b Find c: a^2 + b^2 = c^2

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct? A) The truck experiences the greater average force. B) The small car experiences the greater average force. C) The small car and the truck experience the same average force. D) The force experienced by each one is inversely proportional to its mass. E) The force experienced by each one is directly proportional to its mass.

C) The small car and the truck experience the same average force. (Newton's 3rd Law)

In a collision between two unequal masses, which mass receives a greater magnitude impulse? A) the larger mass B) the smaller mass C) They receive equal impulses

C) They receive equal impulses Impulse = F(forces are equal and opposite)t(equal)

In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is Before: 2 kg @ 3.0 m/s => + 8 kg @ 1.5 m/s => After: 2 kg @ 1.8 m/s => + 8 kg @ 1.8 m/s => A) perfectly elastic B) partially inelastic C) completely inelastic D) characterized by an increase in kinetic energy E) not possible because momentum is not conserved

C) completely inelastic Same V

If you want to double the momentum of gas molecule, by what factor must you increase its kinetic energy? A) √2 B) 2 C) 2√2 D) 4 E) 16

D) 4

An egg falls from a bird's nest in a tree and feels no effects due to the air. As it falls, A) only its kinetic energy is conserved B) only its momentum is conserved C) both its kinetic energy and its momentum are conserved D) only its mechanical energy is conserved E) both its mechanical energy and its momentum are conserved

D) only its mechanical energy is conserved