are Two identical billiard balls of diameter 5 cm each

Last updated: 6/9/2023

are Two identical billiard balls of diameter 5 cm each moving with a speed of 3 m s roll without slipping towards each other on a horizontal rectangular U shaped trough that is sufficiently deep that the balls clear of its base see figure The resulting instantaneous collision is perfectly elastic and during it each ball reverses its linear velocity though their angular velocities are not affected How wide does the trough need to be approximately for balls to collide twice