Chapter 2, Problem 46A

To determine

The circumstances under which it is valid to treat an object as a particle while solving motion problems.

Explanation of Solution

Introduction:

In solving motion problems, the particle model is to track the motion of athlete, runner, car or any other moving object. In the particle model, the mass of the entire object is assumed to be concentrated at a single point and hence, the object is replaced by single point while tracking the motion of an object. For an object to be treated as a particle, it has to satisfy certain conditions.

In order to treat an object as a particle, the conditions that have to be satisfied are as follows:

1. The size of the object should be very small in comparison to the distance moved by the object.

2. The object’s internal motion is not significant and can be ignored.

Conclusion:

Thus, an object can be treated as a point particle when particle’s internal motions are insignificant and particle’s size is too tiny in comparison to the distance travelled by the object.