In an experiment, a variable, position-dependent force F(x) is exerted on a block of mass 1.0kg that is moving on a horizontal surface. The frictional force between the block and the surface has a constant magnitude of Ff . In addition to the final velocity of the block, which of the following information would students need to test the hypothesis that the work done by the net force on the block is equal to the change in kinetic energy of the block as the block moves from x=0 to x=5m ?
(A) The function F(x) for 0 < x < 5 and the value of Ff.
(B) The function a(t) for the time interval of travel and the value of Ff.
(C) The function F(x) for 0 < x < 5, the block's initial velocity, and the value of Ff.
(D) The function a(t) for the time interval of travel, the time it takes the block to move 5 m, and the value of Ff.
(E) The block's initial velocity, the time it takes the block to move 5 m, and the value of Ff.