# Point of application of force

## Homework Statement

Three forces are applied to a square plate of side a. The point of application (on side BC) of the resultant force is ?

## The Attempt at a Solution

Resultant force acts along AC with magnitude 2F. How to find the point of application that too on a given side?

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## Answers and Replies

PhanthomJay
Homework Helper
Gold Member
The resultant force does not act along a line from A to C. The resultant force is the force that is the vector sum of the individual forces, the line of action of which produces the same torque about any point as the sum of the torques of the individual forces about that point. It is often best to first break each force into its component forces.

SammyS
Staff Emeritus
Homework Helper
Gold Member
To make things easier, look at the torque about point A.

You do have the correct direction (to the right) and magnitude for the resultant force, just not the correct location.

the line of action of which produces the same torque about any point as the sum of the torques of the individual forces about that point.

I did not know about this. Now the problem is a piece of cake
Thanks!