Work, Energy and Power

What is the SI unit of work done?

A force of 10 N acts on an object and displaces it by 5 m in the direction of the force. What is the work done?

Which of the following is an example of zero work done?

The kinetic energy of a body is given by \( K.E. = \frac{1}{2}mv^2 \). If the velocity of the body is doubled, its kinetic energy becomes:

A body of mass 2 kg is moving with a velocity of 3 m/s. What is its kinetic energy?

If the potential energy of a body at height h is given by \( U = mgh \), what will be its potential energy at half the height?

Power is defined as the rate of doing work. If a machine does 500 J of work in 10 seconds, what is its power?

A force \( \vec{F} = 5\hat{i} + 3\hat{j} \) N acts on a particle which moves from origin to point \( \vec{r} = 2\hat{i} + 4\hat{j} \) m. Calculate the work done by the force.

A body of mass 5 kg is dropped from a height of 20 m. Assuming \( g = 10 \ \text{m/s}^2 \), what is its velocity just before hitting the ground?

A block is pulled up an inclined plane of length 10 m and height 5 m with a force of 100 N parallel to the incline. Calculate the work done by the force.