Exam 7: Linear Momentum

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?

Three masses are located in the x-y plane as follows: a mass of 6 kg is at (0 m, 0 m) , a mass of 4 kg is at (3 m, 0 m) , and a mass of 2 kg is at (0 m, 3 m) . Where is the center of mass (or center of gravity) of the system?

Which of the following quantities are units of momentum? (There could be more than one correct choice.)

An 80-kg man is skating northward and happens to suddenly collide with a 20-kg boy who is ice skating toward the east. Immediately after the collision, the man and boy are seen to be moving together at 2.5 m/s in a direction $60 ^ { \circ }$ north of east. How fast was the boy moving just before the collision?

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 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides directly with a stationary seal of mass 200 kg. The seal grabs onto the whale and holds fast. What is the Speed of these two sea creatures just after their collision? You can neglect any drag effects of the Water during the collision.

A 0.17-kg baseball is thrown with a speed of 38 m/s and it is hit straight back toward the pitcher with a speed of 62 m/s. What is the magnitude of the impulse exerted upon the ball by the bat?

A block of mass m=4.4 kg, moving on frictionless surface with a speed $v _ { \mathrm { i } } = 9.2 \mathrm {~m} / \mathrm { s }$ makes a sudden perfectly elastic collision with a second block of mass M , as shown in the figure. The second block is originally at rest. Just after the collision, the 4.4-kg block recoils with a speed of $v _ { \mathbf { f } } = 2.5 \mathrm {~m} / \mathrm { s }$ What is the mass M of the second block?

Which of the following quantities are units of impulse? (There could be more than one correct choice.)

Calculate the impulse due to a force of 4.5 N that lasts for 1.4 s.

A 550-g ball traveling at 8.0 m/s undergoes a sudden head-on elastic collision with a 250-g ball traveling toward it also at 8.0 m/s. What is the speed of the 250 -g mass just after the collision?

An 8.0-g bullet is suddenly shot into a 4.0-kg block, at rest on a frictionless horizontal surface, as shown in the figure. The bullet remains lodged in the block. The block then moves against a spring And compresses it by 8.9 cm. The force constant (spring constant) of the spring is 1400 N/m. What Is the magnitude of the impulse on the block (including the bullet inside) due to the spring during The entire time interval during which the block compresses the spring?

There must be equal amounts of mass on both sides of the center of mass (or center of gravity) of a system.

A block of mass m=5.6 kg, moving on a frictionless surface with a velocity of $v _ { \mathrm { j } } = 6.5 \mathrm {~m} / \mathrm { s }$ right, collides with a block of mass M at rest, as shown in the figure. After the collision, the 5.6-kg block recoils with a velocity of $v _ { f } = 0.70 \mathrm {~m} / \mathrm { s }$ the magnitude of the average force on the 5.6-kg block, while the two blocks are in contact?

In a police ballistics test, a 2.00-g bullet suddenly hits and becomes embedded in a 5.00-kg wood block which is hanging from a 1.20-m long string. This causes the block to swing through an arc of 3)50°. What was the speed of the bullet just before it hit the block?

A 328-kg car moving at 19.1 m/s in the +x direction hits from behind a second car moving at 13.0 m/s in the same direction. If the second car has a mass of 790 kg and a speed of 15.1 m/s right after the collision, what is the velocity of the first car after this sudden collision?

Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in the front throws a very massive ball toward the back, and the Person in the back catches it. After the ball is caught, the canoe is

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash Head-on into a stationary brick wall. In neither case does your car bounce back from the thing it Hits, and the collision time is the same in both cases. Which of these two situations would result in The greater impact force on your car?

A 0.140-kg baseball is thrown with a velocity of 27.1 m/s.It is struck by the bat with an average force of 5000 N, which results in a velocity of 37.0 m/s in the opposite direction from the original Velocity. How long were the bat and ball in contact?

A block of mass m=3.6 kg, moving on a frictionless surface with a speed $v _ { \mathrm { i } } = 9.3 \mathrm {~m} / \mathrm { s }$ sudden perfectly elastic collision with a stationary block of mass M , as shown in the figure. Just after the collision, the 3.6-kg block recoils with a speed of $v _ { f } = 2.7 \mathrm {~m} / \mathrm { s }$ other block? What is the speed V of the