Chapter 4, Problem 19Q

A block is given a brief push so that it slides up a ramp. After the block reaches its highest point, it slides back down, but the magnitude of its acceleration is less on the descent than on the ascent. Why?

To determine

Why the magnitude of the acceleration of the block is less than descent than on the ascent.

Answer to Problem 19Q

Solution:

Acceleration is less on the descent because friction opposes the motion.

Explanation of Solution

Descent is the gain in negative altitude and ascent is the gain in positive altitude. It means both are opposite to each other.

When the block is moving up then the gravitational force and the frictional force are parallel and act together.

When the block moves downward then the gravitational and frictional force are parallel but in opposite direction and hence, oppose.

That’s why the acceleration is less on the descent because friction opposes the motion.