Chapter 6, Problem 70A

The net force acting on an object and the resulting acceleration are always in the same direction. You can demonstrate this with a spool. If the spool is gently pulled horizontally to the right, in which direction will it roll?

To determine

The direction of rolling of spool.

Answer to Problem 70A

The spool will roll in the right direction since net force and acceleration will be in same direction.

Explanation of Solution

Introduction:

According to Newton’s second law of motion, an object accelerates due to the force applied. Mathematically it can be written as,

  $F=m\times a$

So, the acceleration applied to the object moves in the same direction in which the force is applied to it.

Consider the spool that is pulled horizontally to the right as shown below.

If force is applied in the right side to pull the thread connected with spool, then the spool will roll in the clockwise direction in order to extract the thread outwards in the right direction using Newton’s Second law of motion.

Conclusion:

Thus, the spool will roll in the right direction.