(a) State two;

(i) laws of solid friction;

(ii) advantages of friction;

(iii) methods of reducing friction.

(b) Draw and label a diagram of a pulley system with velocity ratio of 5.

(c)(i) Show that the efficiency L, force ratio M.A. and the velocity ratio V.R. of a machine are related by the equation \(E =  \frac{M.A.}{V.R}\)  x 100%. 

(ii) The efficiency of a machine is 80%. Calcuate the work done by a person using the machine to raise a load of 300 kg through a height of 4 m.[ g = 10 ms\(^{-2}\) ]

(a) With the aid of ray diagrams, explain total internal reflection.

(b) Describe, with the aid of a labelled diagram, the essential features of an astronomical telescope in normal adjustment.

(c) A converging lens forms a real image of a real object. If the magnification is 2 and the distance between the image and the object is 90.0 cm, determine the

(i) focal length of the lens;

(ii) object distance for which the image would be the same size as the object.

(a)(i) Name and explain the common defects of a primary cell.

(ii) State two advantages of a secondary cell over a primary cell.

(b) Draw a labelled diagram to show the essential parts of a dry leclanche cell.

(c)(i) Explain why six accumulators each of e.m.f 2V connected in series can be used to start the engine of a car whereas eight dry cells each of e.m.f 1.5 V connected in series cannot be used.

(ii) Name the materials used for the positive terminal, the negative terminal and the electrolyte in a

I. leclanche cell;

II. charged lead acid accumulator.

(a) Define

(i) proton number;

(ii) nucleon number;

(iii) isotopes.

(b) A nuclide \(^A_ZX\) emits \(\beta\)-particle to form a daughter nuclide Y. Write a nuclear equation to illustrate the charge conservation.

(c) The radioactive nuclei \(^{210}_{84}P_o\) emits an \(\alpha\) - particle to produce \(^{206}_{82}P_b\). Calculate the energy, in MeV, released in each disintegration.

Take the masses of  \(^{210}_{84}P_o\) = 209.936730 u;

\(^{206}_{82}P_b\) = 205.929421 u;

\(^{4}_{2}He\) = 4.001504 u;

and that 1u = 931 MeV

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

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

(ii) State two precautions necessary to obtain accurate results in the experiment described in (b)(i) above.

(c) A bullet of mass 120 g is fired horizontally into a fixed wooden block with a speed of 20 ms\(^{-1}\). If 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.