In the figure, the block B of mass m starts from rest at the top of a

1.	In the figure, the block B of mass m starts from rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground. B slides down onto the ground, moves along it with a speed v, has an elastic collision with the wall, and climbs back onto W.(a) B will reach the top of W again. (b) From the beginning, till the collision with the wall, the centre of mass of ‘B plus W’ does not move horizontally. (c) After the collision, the centre of mass of ‘B plus W’ moves with the velocity 2mv / m + M.(d) When B reaches its highest position on W, the speed of W is 2mv / m + M .
Answer» Correct Answer is: (a, c, & d) The horizontal momentum of the system is conserved (= 0) till the collision, as there are no horizontal forces acting on the system. At the collision, an additional impulse 2mv is given by the wall to the system.

In the figure, the block B of mass m starts from rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground. B slides down onto the ground, moves along it with a speed v, has an elastic collision with the wall, and climbs back onto W.(a) B will reach the top of W again. (b) From the beginning, till the collision with the wall, the centre of mass of ‘B plus W’ does not move horizontally. (c) After the collision, the centre of mass of ‘B plus W’ moves with the velocity 2mv / m + M.(d) When B reaches its highest position on W, the speed of W is 2mv / m + M .

Answer»

Correct Answer is: (a, c, & d)

The horizontal momentum of the system is conserved (= 0) till the collision, as there are no horizontal forces acting on the system. At the collision, an additional impulse 2mv is given by the wall to the system.

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