試題詳解

49. A 1.0-kg ball is attached to the end of an incompressible massless rod of length 1.0 m to form a pendulum as shown in the figure below. The pendulum is released at position 1 with velocity V₁ = 0 m/s. At the lowest point of its swing, while it is moving horizontally, the ball collides head-on with a 0.80-kg block initially resting on a frictionless surface at position 2. After the collision, the speed of the block is found to be 3.0 m/s. What is the speed of the ball after the collision?
(A)0.0 m/s
(B)2.0 m/s to the left
(C)3.0 m/s to the right
(D)3.0 m/s to the left
(E)6.0 m/s to the right