A block of mass m moving with a velocity `v_(0)` on a smooth horizontal surface strikes and compresses a spring ofstiffuess k till mass coines to rest as shown in the figure. This phenomenon is observed by two observers :
(a) Standing on the horizontal surface
(b) standing on the block

Accoording to the observer A :

Options

A. the kinetic energy of the block is converted into the potential energy of the spring
B. the mechanical energy of the spring-mass system is conserved
C. the block loses its kinetic energy because of the negative work done by the conservative force of spring
D. all of the above

Answer

D