Question

A smooth sphere A is moving on a frictionless horizontal plane with angular speed $\omega$ and centre of mass velocity v. It collides elastically and head on with an identical sphere B at rest. Neglect friction everyone. After the collision, their angular speeds are ${\omega }_A$ and ${\omega }_B$, respectively. Then

• A. ${\omega }_A$ < ${\omega }_B$
• B. ${\omega }_A$ = ${\omega }_B$
• C. ${\omega }_A$ = $\omega$
• D. ${\omega }_B$ = $\omega$

Answer 1

The correct option is C ${\omega }_A$ = $\omega$

A collision is elastic and head on and both have the same mass, they will exchange

velocity

The angular speed of spheres will remain unchanged.

as the torque is zero

${\omega }_A=\omega$

${\omega }_B=0$