Question

Explain torque with an example.

Answer 1

Hint: It can either be static or dynamic. Static torque is a torque that does not produce an angular acceleration.

Formula used:
$\tau = F.r.\sin \theta $

Complete step by step solution:
Torque is the measure of the force that can cause an object to rotate about an axis. Force is what causes an object to accelerate in linear kinematics. Similarly, torque is what causes an angular acceleration. Hence, torque can be defined as the rotational equivalent of linear force. The point where the object rotates is called the axis of rotation.
Torque can either be static or dynamic. Static torque is a torque that does not produce an angular acceleration. A few examples of static torque are as follows:
• A person pushing a closed-door is applying a static door because the door isn’t rotating despite the force applied.
• Pedaling a cycle at a constant speed is also an example of static torque as there is no acceleration.
Torque calculation: A simple way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force.
Now, from the above observation, we conclude that torque produced depends on the magnitude of the force and the perpendicular distance between the point about which torque is calculated and the point of application of force. So, mathematically torque is represented as
$\tau = F.r.\sin \theta $
Examples of Torque
F = 5N
r = 4m
\[sin\theta {\text{ }} = {\text{ }}30^\circ \]
Putting these values we have,
\[\tau {\text{ }} = {\text{ }}5{\text{ }} \times {\text{ }}4{\text{ }} \times {\text{ }}sin{\text{ }}30^\circ \]
\[\tau {\text{ }} = {\text{ }}10{\text{ }}N - m\]

Note: Some of the real-life examples involving torque are that of a see-saw or in automobiles engines. Torque is defined as the product of force and the perpendicular distance between the force acting point and the pivot point.