# KCSE Past Papers 2015 Physics paper 1 (232/1) PHYSICS

Paper 1

(THEORY)

SECTION A: (25 marks)

Answer ALL the questions in this section in the spaces provided.

Figure 1 shows part of the main scale of a vernier calipers. Insert the vernier scale to the main scale, to show a reading of 3.14 cm. (1 mark)

2 Figure 2 (a) shows the initial reading of a burette used to measure the volume of oil. After 50 drops of the oil were run out, the ﬁnal reading was as shown in Figure 2 (b) Determine the volume of one drop of oil. (2 marks)

3 A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm. Determine the moon’s gravitational strength. ( Take gravitational ﬁeld strength on earth as I0 Nkg-1) (3 marks)

4 State two factors that determine the pressure at a point in a liquid. (2 marks)

5 A student wearing sharp pointed heeled shoes is likely to damage a soft wooden ﬂoor. Explain. (2 marks)

6 Figure 3 shows the arrangement of molecules in the three states of matter (a) Name the process represented by the arrow. (1 mark)

(b) State the reason for the arrangement of molecules in state 3. (l mark)

7 Two containers A and B of equal dimensions but different metals are ﬁtted with identical glass casings. The two containers initially at the same temperature are simultaneously ﬁlled with boiling water. It is observed that the glass casing on A breaks earlier than the one on B.

Explain this observation. (2 marks)

Figure 4 shows a uniform metal rod balanced at it’s centre by different forces. Determine the value of T

(3 marks)

Figure 5 shows air ﬂowing through a pipe of different cross—section areas. Two pipesA and B are dipped into water. Explain the cause of the difference in the levels of water in the pipes A and B. (2 marks)

10 A balloon is ﬁlled with hydrogen gas and then released into the air. It is observed that as it rises higher into the air it expands. Explain why it expands. (2 marks)

11 A person carrying a heavy luggage using one hand leans away from the luggage. State the reason for this. (1 mark)

12 Figure 6 shows a glass with water fitted with two identical thermometers A and B. It is heated as State with a reason which one of the two thermometers shows a higher temperature (2 marks)

13 Mechanics is one of the branches of physics. State what it deals with (1 mark)

SECTION B: (55 marks)

Answer ALL the questions in this section in the spaces provided.

14 (a) Figure 7 (drawn to scale) shows a section of tape after passing through a ticker timer operated at a frequency of 50 Hz. The tape is attached to a trolley moving in the direction shown. (i) Determine the velocity between:

(I) P and Q; (4 marks)

(II) X and Y. (2 marks)

(ii) Determine the acceleration of the trolley. (3 marks)

(b) Two bodies of masses 5 kg and 8 kg moving in the same direction with velocities 20 ms-1 and 15 ms-1 respectively collide inelastically. Determine the velocity of the bodies after the collision. (4 marks)

15 (a) Figure 8 shows a 200 g mass placed on a frictionless surface and attached to a spring. The spring is compressed and released. Given that the elastic potential energy of the compressed spring is 2.7 X 10-2 J, determine the maximum speed with which the block moves after it is released. (4 marks)

(b) In a wheel and axle system, state the advantage of having a large wheel diameter compared to the axle diameter for a frictionless system. (1 mark)

(c) A body is released from a height h. Sketch a graph of potential energy against kinetic energy as the body falls to the ground. (2 marks)

(d) Figure 9 shows a hydraulic lift system. The radius of the small piston is 3 cm while that of the larger piston is 9 cm. A force of 90 N is applied to the smaller piston. Determine the:

(i) maximum load that can be lifted. (3 marks)

(ii) efﬁciency of the system. (3 marks)

16 (a) Figure 10 shows an incomplete set up that can be used in an experiment to determine the speciﬁc heat capacity of a solid of mass m by electrical method. (i) Complete the diagram by inserting the missing components for the experiment (2 marks)

(ii) Other than temperature, state three measurements that should be taken. (3 marks)

(iii) The ﬁnal temperature was recorded as 0. Write an expression that can he used to determine the speciﬁc heat capacity of the solid. (2 marks)

12 (b) State three ways of increasing the sensitivity of a liquid-in-glass thermometer. (3 marks)

17 (a) Figure 11 shows a graph of pressure (p) against volume (v) for a ﬁxed mass of a gas at constant temperature. (b) Explain the pressure law using the kinetic theory of gases. (3 marks)

(c) 20 cm3 of a gas exerts a pressure of 760 mmHg at 25°C. Determine the temperature of the gas when the pressure increases to 900 mml-lg and the volume reduces to 15 cm3. (4 marks)

(d) Figure 12 shows the path of a light ball projected horizontally. The ball is then made to spin in an anticlockwise direction as it moves:

(i) on the same axis, sketch the new path of the ball. (1 mark)

(ii) explain how the ball attains the new path. (2 marks)

18 (a) Figure 13 shows a pendulum bob suspended by a thread moving in a horizontal circle. (i) Name two forces acting on the pendulum bob as it moves (2 marks)

(ii) State what happens to each of the forces when the angular velocity of the pendulum bob is increased. (2 marks)

(iii) State two applications of uniform circular motion in daily life. (2 marks)

(b) Figure 14 shows a block ﬂoating in water. When the water is heated; it is observed that the block sinks further. Explain this observation. (2 marks)

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