Chapter 4: Q20. (page 99)

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?

Short Answer

Expert verified

The block’s acceleration will be less on the descent than on the ascent.

Step by step solution

Step 1. Determine the forces acting on the block

When the block is moving up a ramp, two forces are exerted on the block; the first one is the component of the weight, and the other is the frictional force due to sliding.

The two forces (weight and frictional force) acting on the block as it slides up are parallel to each other. The direction of these forces is down the plane, causing a greater magnitude of force as well as acceleration.

Step 2. Determine the magnitude of acceleration on the descent and ascent

As the block comes down the ramp, the directions of the component of weight and frictional force are opposite to each other. The frictional force acts toward the upward direction.

So, due to the opposite directions, the magnitude of the force is small, and as a result, acceleration will be less. Thus, the acceleration is less on the descent as compared to the ascent.