試題詳解

39. In the figure, a block of mass m = 20.0 kg slides through a horizontal frictionless ground at a speed of v = 0.50 m/s. It then compresses the spring with spring constant k = 5.0 N/m. When the block decelerates to a stop, by what distance d is the spring compressed?
(A) 0.5 m
(B) 1.0 m
(C) 1.5 m
(D) 2.0 m
(E) 2.5 m