A cart P of unknown mass moves without friction along a straight

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A cart P of unknown mass

m

moves without friction along a straight, horizontal air-track with a speed of

4.0\,\text{m}\,\text{s}^{-1}

. It collides head-on with a stationary cart Q of mass

0.50\,\text{kg}

. After the collision cart P is observed to reverse its direction and move with a speed of

1.0\,\text{m}\,\text{s}^{-1}

while cart Q moves forward with a speed of

3.0\,\text{m}\,\text{s}^{-1}

. Answer the following parts. (i) Write the two independent equations that relate the velocities before and after the collision. (ii) Using these equations, obtain an expression for the unknown mass

m

. (iii) Calculate the numerical value of

m

correct to two significant figures.

Related theory

Collisions
Conservation of momentum
Linear momentum
Collisions in one dimension
Work, Energy and Power
Elastic and inelastic collisions

Browse the problem library