Momentum and conservation of linear momentumEdexcel A-Level Physics: Flashcards

What these 13 flashcards ask

Define momentum.
What are the units of momentum?
State the principle of conservation of linear momentum.
What is a closed system?
Why is momentum a vector in a collision calculation?
How does Newton's third law lead to conservation of momentum?
What is Newton's second law in terms of momentum?
What is the total momentum before an explosion from rest?
A gun fires a bullet forwards. Why does the gun recoil?
Why does the lighter object move faster after an explosion from rest?
Write the momentum equation for objects that stick together.
Give two reasons why momentum may appear not to be conserved in an experiment.
How can friction be compensated in a trolley experiment?

Exam questions on Momentum and conservation of linear momentum

Two trolleys, A and B, each of mass 0.60 kg, are on a straight horizontal track where friction is negligible. Trolley A moves to the right at 1.5 m s⁻¹ towards trolley B, which moves to the left at 1.5 m s⁻¹. Take movement to the right as positive.
The trolleys collide and stick together. Deduce their velocity immediately after the collision, giving a reason.2 marks
A student of mass 55 kg stands on a skateboard of mass 3.0 kg, at rest on smooth level ground. She throws a medicine ball of mass 4.0 kg horizontally forwards so that it leaves her hands at 5.0 m s⁻¹ relative to the ground.
Explain, using Newton's laws, why the student moves backwards when she throws the ball.2 marks
A railway truck of mass 8000 kg rolling at 3.0 m s⁻¹ along a straight level track collides with a stationary truck of mass 12 000 kg. The trucks couple together and move off as one.
Calculate the velocity of the coupled trucks immediately after the collision.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).