A student investigates head-on collisions between low-friction carts on a horizontal track
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A student investigates head-on collisions between low-friction carts on a horizontal track. In one trial, Cart A of mass mA is released from rest at the top of a gentle ramp and acquires a small horizontal speed just before it strikes and sticks to Cart B, which is initially at rest on the main level of the track.
Assume rolling friction and air resistance are negligible during the short time interval of the collision.
(a) Identify the system you would analyze during the instant of collision and describe all external forces that act on that system during that instant.
(b) Explain why the horizontal component of the system’s motion immediately after the collision cannot depend on the gravitational force that acted while Cart A rolled down the ramp.
(c) Qualitatively compare the total kinetic energy of the two-cart system just before and just after the collision. State whether it increases, decreases, or remains the same, and justify your answer without performing calculations.
(d) Suppose a second trial is performed in which Cart B has twice its original mass while all other conditions remain unchanged. Predict whether the fractional loss of the system’s kinetic energy during the collision will be greater than, less than, or equal to that in the first trial. Justify your prediction.