A 1.6-kg block slides down a plane (inclined at 25$\degree$ with the horizontal)at a constant speed of 2.0 m/s.At what rate is the frictional force changing the mechanical energy of the block?
A)+28 W
B)+13 W
C)-13 W
D)-28 W
E)+6.5 W

Question

Quizplus · Accepted Answer

The block is moving at a constant speed, meaning the net force is zero. The frictional force is doing negative work equal to the gravitational component along the incline. The rate of change of mechanical energy is the work done by friction, which is negative.

A 16-Kg Block Slides Down a Plane (Inclined at 25 °\degree°

A 16-Kg Block Slides Down a Plane (Inclined at 25 $\degree$