Questions 15-17(含图)
A block of mass m is on a rough horizontal surface and is attached to a spring with spring constant k.
The coefficient of kinetic friction between the surface and the block is m. When the block is at position x = 0, the spring is at its unstretched length. The block is pulled to position x = +x0 , as shown above, and released from rest. The block then travels to the left and passes through x = 0 before coming momentarily to rest at position x = - x0/2 .
Which of the following is a correct expression for the kinetic energy of the block as it first travels through position $$x = 0$$?