How do you prove that work is done equal to change in kinetic energy?
How do you prove that work is done equal to change in kinetic energy?
Key Points
- The work W done by the net force on a particle equals the change in the particle’s kinetic energy KE: W=ΔKE=12mv2f−12mv2i W = Δ KE = 1 2 mv f 2 − 1 2 mv i 2 .
- The work-energy theorem can be derived from Newton’s second law.
- Work transfers energy from one place to another or one form to another.
Why is work equal to the change in kinetic energy?
According to the work-energy theorem, the work done on an object by a net force equals the change in kinetic energy of the object. Essentially kinetic energy is the energy used for motion. When things move, they can do work. Now that load will have potential energy that can be transformed into kinetic energy and so on.
Is work equal to the change in potential energy?
Generally speaking in physics we are interested in conservative forces, and one of the definitions of a conservative force is that the work done is equal to the change in potential energy. This normally means energy neither leaves or enters the system we are considering.
What is the work done by frictional force?
The work done by friction is the force of friction times the distance traveled times the cosine of the angle between the friction force and displacement; hence, this gives us a way of finding the distance traveled after the person stops pushing.
What is the work done by a force equal to?
Work done on an object along a given direction of motion is equal to the force times the displacement times the cosine of the angle.
Are work done and energy same?
Energy is the quantity required to perform work on or by an object. Energy is transferred to an object and work is done on the object or by the object. They are not the same but energy is added to the object and then work is done by the object or on the object using the energy transferred to the object.
Can work done by friction force be positive?
The work done by frictional force will be positive when the displacement of the body is in the direction of the force. Since, the direction of motion of the block and the direction of frictional force is opposite to each other, the work done by friction is negative. The work done by friction can also be zero.
Is work done by frictional force always negative?
A work done by friction is always negative.
What is work done by force?
Work is done when energy is transferred from one store to another. Work is also done when a force causes an object to move. When work is done against frictional forces acting on an object, the object’s temperature increases.