Two friends
A and
B (each weighing
40kg) are sitting on a frictionless platform some distance
d apart. A rolls a ball of mass
4kg on the platform towards
B which
B catches. Then
B rolls the ball towards
A and
A catches it. The ball keeps on moving back and forth between
A and
B. The ball has a fixed speed of
5m/s on the platform.
(a) Find the speed of A after he rolls the ball for the first time.
(b) Find the speed of A after he catches the ball for the first time.
(c) Find the speeds of A and B after the ball has made 5 round trips and is held by A.
(d) How many times can A roll the ball?
(e) Where is the centre of mass of the system 'A+B+ball" at the end of the nth trip?