Answer to Question #264293 in Mechanics | Relativity for john

Question

A block is pulled across a rough, horizontal surface from point A to point B by a

force, P as shown in the figure. The magnitude of the force of friction acting on

the block between A and B is 1.2 N, and points A and B are 0.50 m apart. If the

kinetic energies of the block at A and B are 4.2 J and 5.8 J, respectively, how

much work is done on the block by the force P between A and B?

Answer 1

$W = \Delta K_E+W_{fric } = (W_1-W_2) + FS = (5.8-4.2)+1.2*0.5=2.2J$