Question

A hollow smooth uniform sphere $A$ of mass $m$ rolls without sliding on a smooth horizontal surface. It collides elastically and head-on with another stationary smooth hollow sphere $B$ of the same mass mm and same radius. The ratio of the kinetic energy of $B$ to that of $A$ just after the collision is

• A. $1:1$
• B. $2:3$
• C. $3:2$
• D. $None$

Answer 1

Answer: (A)

$1:1$

The sphere is rolling on a smooth surface i.e., no energy is lost to friction and the kinetic energy of sphere A is transferred to the sphere B without any loss as the collision is head-on and elastic.

Thus, the kinetic energy of sphere A and sphere B are equal their ratio will be 1:1