Question

Door hinge is about $1.5m$ away from the handle. And a boy applies a force of $4N$, the moment of force will be
A. $5.5Nm$
B. $2.66Nm$
C. $6Nm$
D. $2.5Nm$

Answer 1

Hint:We are given that a boy applies a force to the hinge of a door. We have to find the moment of force on the boy. This problem is being taken from the principles of moments chapter. Here, the formula to be applied is the multiplication of the force and the distance. So, we got our answer.

Complete step by step answer:
We are provided with,
Distance from the door $\left( d \right) = 1.5m$
Force applied $\left( F \right) = 4N$
Moment of force =?
From the formula of moment of force which is equal to multiplication of the force applied to the distance of the object from the applied force.
Moment of force = distance $ \times $ force
$
Moment\, of\, force = 1.5 \times 4 \\
\therefore Moment\, of\, force = 6 $
Hence, the moment of force is $6Nm$

So, the correct option is C.

Additional information:
Moment of force is the rotational effect of a force, which is equal to the force multiplied by the perpendicular distance between a pivot and the force. The moment of a force is related to the size of the force and the size of the perpendicular distance between the force and pivot. The larger the perpendicular distance the larger the turning effect (moment).

Note:The units for moment of force is Newtons-meter $\left( {Nm} \right)$. Moment of force describes the tendency of a body to rotate about its specific axis. It is a vector quantity. Moment of force is often called torque.Hinges are placed on the door edges from where it will fold open. It ensures the quality of the door used.