A 2.0-kg block slides down a plane (inclined at 40$\degree$ with the horizontal)at a constant speed of 5.0 m/s.At what rate is the gravitational force on the block doing work?
A)+98 W
B)+63 W
C)zero
D)+75 W
E)-75 W

Question

Quizplus · Accepted Answer

The gravitational force does work at a rate equal to the component of the gravitational force along the incline times the speed. This is calculated as m*g*sin(40°)*v = 2.0 kg * 9.8 m/s² * sin(40°) * 5.0 m/s = 63 W.

A 20-Kg Block Slides Down a Plane (Inclined at 40 °\degree°

A 20-Kg Block Slides Down a Plane (Inclined at 40 $\degree$