Question

State work energy principle.

Answer 1

Answer:

The work-energy principle states that an increase in the kinetic energy of a rigid body is caused by an equal amount of positive work done on the body by the resultant force acting on that body. Conversely, a decrease in kinetic energy is caused by an equal amount of negative work done by the resultant force.

Examples,

(1) A car is accelerating constantly. Here velocity is increasing. As a result of, kinetic energy is also increasing. So positive work is done.

(2) A ball is dropped from a certain height. Here velocity of the ball is increasing gradually due to gravitational acceleration. As a result of which kinetic energy increases and positive work is done.

(3) A motor bike applies break and comes into rest after few second. Here work done by the break is negative. Because speed decreases, for which K.E also decreases.

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hope it helps....

Answer 2

Work done is a product of force and displacement, but only if the dot product is removed.

Explanation:

• According to the work energy theorem, work done by a force in displacing a body measures the change in kinetic energy of the body when a force does some work on a body, and when an opposing force is put on a body, the kinetic energy of the body increases by the same amount.
• The kinetic energy of the object diminishes. The decrease in kinetic energy of the bodies is proportional to the amount of work done by the body against the opposing force.
• As a result, work and kinetic energy are the same thing. We must suppose that the force's work is only effective in modifying the body's kinetic energy.