Conduction is the method of transfer of heat in

1. liquids
2. solids
3. gases
4. vacuum

(a) If the moment of force is assigned a negative sign, then will the turning tendency of the force be clockwise or anti-clockwise?

(b) Complete the following nuclear reactions given below

I. $^{238}_{92}\text{P} \overset{\alpha} \longrightarrow \text{Q} \overset{\beta} \longrightarrow \text{R} \overset{\beta} \longrightarrow \text{S}$

II. $^{A}${Z}\text{X} \overset{\alpha} \longrightarrow \text{X}{1} \overset{\gamma} \longrightarrow \text{X}{2} \overset{2\beta} \longrightarrow \text{X}{3}

(a) Define couple.

(b) State the SI unit of moment of couple.

(a) What is meant by an ideal machine?

(b) Write a relationship between the mechanical advantage (MA) and velocity ratio (VR) of an ideal machine.