What Is A Moment In Physics? (gcse And A Level)

A moment is the turning effect of a force. The equation to calculate a moment is:

Moment = Force (perpendicular to the pivot) x distance (from the pivot)

For example, consider a horizontal bar of negligible weight. One end of the bar is screwed into the wall (and acts like a pivot). If a weight of 30 N is applied 10 m away from the pivot, what is the moment due to the force?

Moment = force x distance

Moment = 30 x 10 = 300 Nm

Another important note is the principle of moments:

For any object in equilibrium, the SUM of the anticlockwise moments = the SUM of the clockwise moments.

Just that definition can earn you marks both at GCSE and A Levels.

Lastly, another important definition that can earn you marks is the centre of mass:

The centre of mass of an object is the point at which a downwards force has no turning effect on the object.

Thank you for reading this article! This was very brief as it is hard to explain complex moment calculations (such as forces at angles) purely over text, so if you have any questions (about this article or any other questions), please let me know!