Question

A body is acted upon by two forces each of magnitude $F$, but in opposite directions. State the effect of the forces if the two forces act at two different points of the body at a separation $r$. Which of the following is/are true?

• A. Resultant force $=0$
• B. moment of forces $=Fr$
• C. The forces tend to rotate the body about the mid-point between the two forces.
• D. All of the above

Answer 1

The correct option is D All of the above

Here we apply two forces of same magnitude but opposite in direction.Hence we have F and - F which makes resultant force as zero.

Moment of force for F is $r\times F$. For force F it has distance r therefore it has moment rF and same with force -F.Hence moment of force is rF.

The forces tend to rotate the body about the mid-point between the two forces.