Work Energy Theorem Examples

Therefore the change in the car s kinetic energy is equal to the work done by the frictional force of the car s brakes.

Work energy theorem examples.

Where w g work done by gravity. Equation for the work energy theorem the most commonly encountered form of the theorem is probably wnet 1 2 mv2 1 2 mv02 where v0 and v are the initial and final velocities of the object and m is its mass and wnet is the net work or total work. A brief overview of energy kinetic energy gravitational potential energy and the work energy theorem for algebra based physics students. The principle of work and kinetic energy also known as the work energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.

The diagram represents a 155 newton box on a ramp. Work energy theorem holds for both positive and negative work done if the work done is positive then final ke increases by amount of the work and if work done is negative then final ke decreases by the amount of work done example 1. W g w n w f k f k i. The term work is used in everyday life quite frequently and we understand that it s an act of doing something.

Therefore we first need to determine the car s kinetic energy at the moment of braking using. In fact the building of the pyramids in ancient egypt is an example of storing energy in a system by doing work on the system. Also here the work done is the work done by all forces acting on the body like gravity friction external force etc. For example consider the following figure according to work energy theorem work done by all the forces change in kinetic energy.

For example you are working right now on your grasp of physics by reading this article. We know that all the car s kinetic energy is lost to friction. This definition can be extended to rigid bodies by defining the work of the torque and rotational kinetic energy. But physics itself might not agree on this.

Some of the energy imparted to the stone blocks in lifting them during construction of the pyramids remains in the stone earth system and has the potential to do work. We apply the work energy theorem. The work energy theorem is useful however for solving problems in which the net work is done on a particle by external forces is easily computed and in which we are interested in finding the particles speed at certain positions of even more significance is the work energy theorem as a starting point for a broad generalization of the concept.