The magnitude of the moment of a force is calculated by which formula?

The magnitude of the moment of a force, often referred to as torque, is calculated using the formula that involves multiplying the force applied by the perpendicular distance from the axis of rotation to the line of action of the force. This relationship is fundamental in mechanics as it describes how much a force acting at a distance can cause an object to rotate about a point or axis.

For instance, when you apply force to a wrench to turn a bolt, the effectiveness of that force in creating rotation depends not just on how hard you push (the magnitude of the force) but also on how far you are from the bolt (the distance). If you push with the same force but from a closer position, the moment generated will be less, illustrating the importance of that perpendicular distance. This concept is crucial in fields like power engineering where mechanical systems often involve rotational forces.

In contrast, the other options provided do not correspond to the calculation of moment. Force multiplied by area relates to pressure, force multiplied by time does not yield a term relevant to moment or torque, and force multiplied by pressure would not provide a moment either. This is why the fourth option stands out as it accurately describes the formula for calculating the moment of a force.