During a billiard-ball demonstration, Ball X slows down after colliding with Ball Y
PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
During a billiard-ball demonstration, Ball X slows down after colliding with Ball Y, while Ball Y speeds up. A student concludes that the collision was inelastic solely because Ball X lost kinetic energy. Which reasoning error most directly leads to the student’s incorrect conclusion?
(a) Failing to compare the total kinetic energy of the two–ball system before and after the collision
(b) Believing that an elastic collision requires the speed of each object to remain unchanged
(c) Assuming that momentum is not conserved in an elastic collision
(d) Neglecting the possibility that some of the translational kinetic energy was converted into rotational kinetic energy