Exam 9: Linear Momentum and Collisions

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

A 900-kg car traveling 30.0° south of east at 12.0 m/s collides with a 750-kg car traveling north at 17.0 m/s. The cars stick together. What is the speed of the wreckage just after the collision?

A batter hits a 0.140-kg baseball that was approaching him at 30.0 m/s and, as a result, the ball leaves the bat at 40.0 m/s in the direction of the pitcher. The ball remains in contact with the bat for 2.0 ms. What is the average force exerted by the bat?

When a ball undergoes a one-dimensional elastic collision with a wall, the velocity of the ball is reversed, while the wall remains stationary. Explain why this does not violate conservation of momentum.

A 320-g air track cart traveling at 1.25 m/s collides elastically with a stationary 270-g cart. What is the speed of the 270-g cart after the collision?

A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of -2.0 m/s. What is the velocity of the yellow ball after the collision?

A 0.140-kg baseball is dropped from rest from a height of 2.2 m above the ground. It rebounds to a height of 1.6 m. What change in the ball's momentum occurs when the ball hits the ground?

When a gun is fired, which has the greater kinetic energy: the bullet or the recoiling gun?

Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward the right with a speed of 0.850 m/s and air track cart B has a mass of 300 g and moves toward the left with a speed of 1.12 m/s. What is the total momentum of the system?

A 14,000-kg boxcar is coasting at 1.50 m/s along a horizontal track when it hits and couples with a stationary 10,000-kg boxcar. What is the speed of the cars after the collision?

An assault rifle fires an eight-shot burst in 0.40 s. Each bullet has a mass of 7.5 g and a speed of 300 m/s as it leaves the gun. What is the average recoil force on the gun during that burst?

A mass of 2 kg traveling at 3 m/s undergoes a one-dimensional elastic collision with a group of four 1-kg masses that are at rest in contact with each other and lined up in the same direction as the velocity of the 2-kg mass. As a result of the collision

A 340-g air track cart traveling at 1.25 m/s collides elastically with a 300-g cart traveling in the opposite direction at 1.33 m/s. What is the speed of the 300-g cart after the collision?

In space, a 4.0 kg metal ball moving 30. m/s has a head-on collision with a stationary 1.0 kg second ball. After the elastic collision, what are the velocities of the balls?

An air track cart with mass m and speed v moving along an air track collides with a stationary cart with a mass m/3. After the collision the first cart has a speed v/2. Is the collision elastic?

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

A 120-g rubber ball is thrown with a speed of 10 m/s at an oncoming 900-kg car which is approaching at 30 m/s, and undergoes a one-dimensional elastic collision with the car. What is the speed of the ball after the collision?

A 500-kg cannon fires a 4.0-kg projectile with a velocity of 500 m/s relative to the ground. What is the recoil speed of the cannon?

An artillery shell 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 shell. II. The total kinetic energy of the fragments is equal to the original kinetic energy of the shell.

A puck with a mass m₁ = 28.0 g moving at 1.00 m/s approaches a stationary puck with a mass m₂ = 102 g on an air table and they undergo a two-dimensional elastic collision. As a result of their interaction, the incident puck moves away with a speed v₁ = 0.785 m/s and the other puck moves away with a speed v₂ in a different direction. What is the angle between the velocities v₁ and v₂?