In the case of rotational motion, it is not the linear kinetic energy but the rotational kinetic energy of the body that is considered in the work-energy principle. Torque is equal to the vector product of the distance of the point of application of force from the axis of rotation and the force. In rotational mechanics, torque is the analogue of force, and so the work done by the force should also be equal to the change in kinetic energy. It can also be said that the work is done to change the kinetic energy of the body. Work done by a force is equal to the change in kinetic energy of the body on which the force is acting. ![]() So, the work done by all the torques will be equal to the change in kinetic energy. This theorem is also valid for rotational motion. We know that, according to the work-energy theorem, the amount of work done is equal to the change in kinetic energy. We can now formulate a relationship between the torque and the work done using this case. This will change the rotational kinetic energy of the body, so some work will be done. This force causes some angular acceleration, and the angular velocity will increase due to the torque. Suppose we have a body that is rotating with some angular velocity ω and we apply a force on it at a distance r from the axis of rotation. We could be asked to give an expression for work done, and this is the most basic expression. unit of torque is Nm.įirst, we will write the expression for work done by a force F which displaces an object by some distance r. The torque is represented by $\tau$ and it acts perpendicular to the plane of r and F, according to the rules of the vector product. The formula for torque produced by a force F acting at a point that is at a distance r from the axis of rotation is given by the vector cross product of F and r. The distance between the point of application of torque and the axis of rotation is known as the moment arm or the lever arm. Torque depends on the distance between the axis of rotation and the point of application of torque, as we will see in a bit. One could naturally ask if torque will change with the change of axis of rotation, and the answer is yes, torque changes with the axis of rotation. The axis about which the torque makes a body rotate is known as the axis of rotation. Similarly, the torque causes a change in the angular acceleration of the body. We know from Newton’s second law of motion that force causes a change in the linear acceleration of a body. It can be called the force that causes a body to rotate about an axis. We all know about forces in linear motion, so torque is just the rotational analogue of the force in rotational motion. For example, when you apply force, the kinetic energy of the object changes, and this is the work that you did on the object. When you do work on any system, the energy of the system is converted from one form to another. ![]() Suppose you push an object by applying some force F, and it is displaced by some distance d, then the work done on the object by that force is the dot product of the force and the distance. If we were to define work done, it refers to the amount of displacement that a force produces when applied to any object. In Physics, work is an important quantity. You spend energy and time reading and understanding everything that is written in this article, and you gain knowledge from it in doing so. For example, while reading this article, you are doing some work, and this work might be beneficial for your studies. Work is just something that we do that requires a bit of mental or physical effort. Located at: en./wiki/work.In our daily life, we often hear about work, and we even do a lot of work. License: CC BY-SA: Attribution-ShareAlike License: CC BY-SA: Attribution-ShareAlikeĬC LICENSED CONTENT, SPECIFIC ATTRIBUTION ![]()
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