A laboratory cart of mass 0.80 kg rolls with unknown speed on a horizontal
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A laboratory cart of mass 0.80 kg rolls with unknown speed u on a horizontal, frictionless track and collides with a 1.60 kg block that is initially at rest. The cart and block stick together on impact and the combined mass then moves up a frictionless incline, rising 0.25 m vertically before momentarily coming to rest.
Ignore rotational motion of the wheels and assume no external horizontal forces act during the collision.
(a) Determine the speed v of the combined cart–block system immediately after the collision.
(b) Calculate the initial speed u of the cart just before impact.
(c) Compute the ratio of the system’s kinetic energy immediately after the collision to the cart’s kinetic energy immediately before the collision, expressing your answer as a percentage.
(d) Explain why mechanical energy is not conserved during the collision but is conserved during the subsequent motion up the incline.