(a) State the conditions for the equilibrium of a rigid body acted upon by parallel forces

(b)(i) Describe an experiment, using the principle of moments, to determine the mass of a metre rule

(ii) State two precautions necessary to ensure accurate results.

(c) A bullet of mass 120g is fired horizontally into a fixed wooden block with a speed of 20ms\(^{-1}\). The bullet is brought to rest in the block in 0.1s by a constant resistance. Calculate the:

(i) magnitude of the resistance;

(ii) distance moved by the bullet in the wood.