PHYSICS · Subjective · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
Two identical smooth carts A and B, each of mass m, move on a horizontal frictionless track along the same straight line. Cart A moves to the right with speed u and cart B moves to the left with the same speed u. Take the rightward direction as positive.
(i) Draw a clearly labelled vector (arrow) diagram showing the momenta of carts A and B just before a perfectly elastic head-on collision and just after the collision (the velocities are exchanged in such a collision).
(ii) Using suitable signs, write the numerical values of the momenta of the two carts before and after collision. Hence verify explicitly that the total linear momentum of the system is conserved.
(iii) If the leftward direction were declared positive instead, rewrite the momenta of the carts before and after collision and state whether momentum conservation still holds. Explain any change (or lack of change) you observe.