Author Question: Starting from rest at t = 0, a 5.0-kg block is pulled across a horizontal surface by a constant ... (Read 80 times)

Diane · **on:** Jul 28, 2018

Starting from rest at t = 0, a 5.0-kg block is pulled across a horizontal surface by a constant horizontal force having a magnitude of 12 N. If the coefficient of friction between the block and the surface is 0.20, at what rate is the 12-N force doing work at t = 5.0 s?
a. 0.13 kW
b. 0.14 kW
c. 0.12 kW
d. 26 W
e. 12 W

Question 2

A 3.0-kg block is on a horizontal surface. The block is at rest when, at t = 0, a force (magnitude P = 12 N) acting parallel to the surface is applied to the block causing it to accelerate. The coefficient of kinetic friction between the block and the surface is 0.20 . At what rate is the force P doing work on the block at t = 2.0 s?
a. 54 W
b. 49 W
c. 44 W
d. 59 W
e. 24 W