Momentum
Which statement correctly defines momentum?
A truck of mass 4000 kg travels north at 15 m s⁻¹. A car of mass 1200 kg travels south at 25 m s⁻¹. What is the difference in the magnitudes of their momenta?
A tennis ball of mass 0.060 kg, initially at rest, is struck by a racket and leaves at 50 m s⁻¹. The racket is in contact with the ball for 4.0 ms. What is the average force exerted on the ball?
Which quantity is a scalar?
A ball of mass 0.15 kg strikes a wall at 20 m s⁻¹ and bounces back at 15 m s⁻¹. Taking the initial direction of the ball as positive, what is the change in momentum of the ball?
A trolley of mass 3.0 kg moving at 4.0 m s⁻¹ collides with a stationary trolley of mass 1.0 kg. The trolleys stick together. What is the velocity of the combined trolleys after the collision?
A cannon of mass 600 kg fires a 4.0 kg cannonball at 120 m s⁻¹. What is the recoil velocity of the cannon?
A car of mass 1500 kg accelerates from rest to 20 m s⁻¹ in 10 s. What is the resultant force on the car?
Car crumple zones are designed to increase the time of a collision. Using the impulse equation, which statement correctly explains why this reduces injury to the occupants?
An object of mass 2.0 kg moves to the right at 5.0 m s⁻¹. If its velocity is doubled, what happens to its momentum?
In a firework explosion, a 0.50 kg shell initially at rest splits into two fragments. Fragment A has mass 0.30 kg and moves to the right at 20 m s⁻¹. What is the velocity of fragment B?
A ball of mass 0.40 kg falls and hits the ground at 10 m s⁻¹, then bounces upward at 8.0 m s⁻¹. The contact time is 0.050 s. Taking upward as positive, what is the average force exerted by the ground on the ball?
A 0.020 kg bullet is fired from a 4.0 kg rifle at 300 m s⁻¹. A student claims the rifle recoils at 300 m s⁻¹. Which error has the student most likely made?
Two ice skaters stand at rest on a frictionless surface. Skater A (mass 60 kg) pushes skater B (mass 40 kg), and skater B moves away at 3.0 m s⁻¹. What is the speed of skater A after the push?
The SI unit of impulse is N s. Which of the following is also equivalent to N s?
A spacecraft of mass 800 kg ejects 2.0 kg of exhaust gas at 500 m s⁻¹ relative to the ground. Assuming the spacecraft was initially at rest, calculate the velocity gained by the spacecraft.
A 50 kg gymnast lands on a mat after a jump and comes to rest. The gymnast’s velocity just before hitting the mat is 6.0 m s⁻¹ downward. The mat brings the gymnast to rest in 0.30 s. If the gymnast instead landed on a hard floor and stopped in 0.010 s, by what factor would the average force increase?
A 1200 kg car travelling east at 20 m s⁻¹ collides head-on with a 800 kg car travelling west at 15 m s⁻¹. The cars lock together after the collision. What is the velocity of the wreckage immediately after the collision?