When work is done on a body by an external force, its

(a) Work is said to be done by a force only when _________

(b) Work done = Force $\times$ _________

(c) The energy of a body is its capacity to do ______

(d) The S.I. unit of energy is ______

(e) The potential energy of a body is due to its ______ and kinetic energy of body is due to its ______

(f) Gravitational potential energy U = mass $\times$ force of gravity on unit mass $\times$ _________

(g) Kinetic energy = $\frac{1}{2}\times mass\times$_________

(h) Power P = ______ / time taken.

(i) The S. I. unit of power is ______

(j) 1 H.P. = ______ W

Question 9
A body is falling from a height h, after it has fallen a height $\frac{h}{2}$, it will possess

(a) only potential energy
(b) only kinetic energy
(c) half potential and half kinetic energy
(d) more kinetic and less potential energy

Which of the following statements is correct about a freely falling body?

1. Total energy is constant.
2. Potential energy changes into kinetic energy.
3. Potential energy decreases.
4. Kinetic energy increases.