Principle of moments:

According to the principle of moments

A body is balanced if the sum of clockwise moments acting on the body is equal to the sum of anticlockwise moments acting on it.

 

Explanation:

Clockwise moment:

A force that turns a spanner in the clockwise direction is generally used to tighten a nut. The torque or moment of force so produced is called the clockwise moment.

 

Anticlockwise moment:

On the other hand, to loosen a nut, the force is applied such that it turns the nut in the anticlockwise direction. The torque or moment of force so produced is called anticlockwise moment.

 

 

Note:

A body initially at rest does not rotate if the sum of all the clockwise moments acting on it is balanced by the sum of all the anticlockwise moments acting on it. This is known as the principle of moments.

 

QUICK QUIZ

1. Can a small child play with a fat child on the seesaw? Explain how?

Ans: Yes, they can play on the see-saw, the fat child has a larger weight that’s mean

Larger force and smaller children have a smaller weight and smaller force. So, to play, a larger weight should be a smaller distance from the center of the see-saw and the smaller weight should be at a larger distance from the center of the see-saw. IN another situation a fat child cannot play with a small child if they have equal distances from the center see-saw.

 

2. Two children are sitting on the see-saw, such that they cannot swing. What is the net torque in this situation?

Ans: Net torque in this situation is zero. Because clockwise torque will cancel the effect of anticlockwise torque.