(a) Name the principle on which a lever works.

(b) Which radiations that are emitted during the decay of a nucleus, having highest penetrating power?

(c) Does the emission of the above-mentioned radiation result in a change in the mass number?

Two bodies A and B have same kinetic energies. Compare their velocities if mass of A is four times the mass of B.

A metre rod made of copper and steel as shown in the diagram. Weights of copper and steel are 10 N and 8 N respectively.

(a) On which part does the centre of gravity lie (0 to 50 or 50 to 100).

(b) Justify your answer.

Draw a graph of potential energy vs height from the ground for a body thrown vertically upwards.