Momentum and conservation of momentumEdexcel International A Level Physics: Flashcards

What these 13 flashcards ask

Define momentum and give its unit.
Is momentum a scalar or a vector?
State Newton's second law in terms of momentum.
What is impulse?
State the principle of conservation of linear momentum.
Write the conservation equation for two bodies in one dimension.
State Newton's third law.
Why do third-law pairs not cancel?
How does Newton's third law lead to conservation of momentum?
A rifle fires a bullet from rest. What is the total momentum afterwards?
Why does a longer collision time reduce the force on a passenger?
A 0.16 kg ball hits a wall at 12 m s⁻¹ and rebounds at 8.0 m s⁻¹. What is its change in momentum?
When can momentum be treated as conserved in a collision?

Exam questions on Momentum and conservation of momentum

A trolley of mass 0.80 kg moving at 1.5 m s⁻¹ along a level, friction-compensated track collides with a stationary trolley of mass 0.40 kg. In one run the two trolleys stick together on impact. In a second run they bounce apart instead.
In the second run the 0.80 kg trolley continues in the same direction at 0.50 m s⁻¹ after the collision. Calculate the velocity of the 0.40 kg trolley after the collision.2 marks
A rifle of mass 3.0 kg is held loosely and is initially at rest. It fires a bullet of mass 0.020 kg, which leaves the barrel with a speed of 400 m s⁻¹ horizontally.
Explain, using Newton's third law, why the rifle recoils and why the total momentum after firing is still zero.2 marks
A tennis ball of mass 0.16 kg hits a vertical wall at right angles at a speed of 12 m s⁻¹. It rebounds along the same line with a speed of 8.0 m s⁻¹. The ball is in contact with the wall for 0.015 s.
Calculate the change in momentum of the ball.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).