### SECTION A (25 Marks)

Answer all the questions in this section in the spaces provided.
1.

The vernier calipers shown in figure 1 has a zero error of -0.55cm.

What is the actual measurement of the object being measured using the vernier caliper?

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3 marks

2.

A crate of mass 40kg is raised by the rope of a crane from the hold of a ship. If the tension in the rope is 480N, find the acceleration of the crate as it rises? Take,g=10N/Kg

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3 marks

3.

Explain how a steel needle is made to float on water.

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2 marks

4.

Using a simple kinetic theory, give two reasons as to why it is necessary to supply energy to change water to steam at 1000C.

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2 marks

5.

Explain why the temperature of methylated spirit decreases when air is blown over it.

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2 marks

6.

How can the moment of a given force be made larger?

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1 marks

7.

Figure 2 below shows an irregular shape of plywood suspended by a thin thread at two different points A and B. In the diagram, mark and label the position of the centre of gravity of the plywood

1 marks

8.

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1 marks

9.

The graph below represents the behavior of a spring in an experiment to investigate the relationship between force and extension produced in spring.

What does region OA indicate?

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1 marks

10.

A space shuttle is in orbit around the earth at a certain height

i) What keeps it in orbit?

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ii) In which direction is it accelerating at each point in itâ€™s orbit.

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iii) How is the centripetal force affected if the shuttle reduces itâ€™s mass by launching a satellite.

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1 marks

11.

Figure 3, below shows the graph of the force applied against the distance covered by a body moving along a certain path.

FIG.3

Determine the work done on the body in the first 45 metres along the path.

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2 marks

12.

Air is blown over a sheet of paper as shown in figure 4.

The paper is lifted up, explain this observation

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2 marks

13.

State the function of the constriction in a clinical thermometer.

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1 marks

14.

Figure 5 shows a water manometer connected to a laboratory gas supply.

What is the excess pressure in terms of length of the water column of the gas supply?

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1 marks

### SECTION B (55 Marks)

Answer ALL the questions in this section in the spaces provided.
15.

Figure 6, illustrates the apparatus for an experiment in which the density of air is to be determined.

a) Describe briefly how the volume of the flask could be measured.

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b) During the determination it is necessary to remove all the air from the flask. How is it possible to know that this has been done?

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c) It is usual to measure the atmospheric pressure and also the room temperature when determining the density of air but not when determining the density of a solid. Why is this necessary?

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d) If one-litre flask is used and mass of air determined is 1.3g, calculate the density of air in standard units. ............................................................................................................................................................................................................................................................

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10 marks

16.

a) According to Archimedes, an object experiences an upthrust force which is equal to the weight of fluid displaced. State the condition necessary for the law to hold.

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b) A simple hydrometer is set up with a test â€“tube (mass=15g, length=12m) with a flat base, and partly filled with lead shot. The tube has a uniform cross-sectional area of 2.0cm2 and 10cm of itâ€™s length are under water. Given the density of water=1000kgm-3. Calculate, with clear explanations.

i) The mass of the lead shot in the tube. (3mks)

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ii) The length of the tube immersed if placed in brine with density 1.25g/cm3 ..........................................................................................................................................................................................................................................................

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iii) The lowest density of liquid in which this tube would float.

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c) When a ship sails from fresh water into the sea, state and explain what happen to the level of itâ€™s plimpsol line. ..........................................................................................................................................................................................................................................................

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10 marks

17.

a) Why can the pressure of a gas not be reduced to zero by cooling.

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b) Using kinetic theory of gases explain how the pressure of a gas rises when heated at constant volume. .......................................................................................................................................................................................................................................................

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c) Figure 7, is a graph that shows the relationship between the pressure of a gas and the reciprocal of itâ€™s volume at constant temperature.

i) State how the pressure and the volume of the gas are related.

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ii) Why would it not be practical for the value of V to go to zero?

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iii) Given that PV=0.82T, where T is the absolute temperature of the gas, determine the value of T from the graph. ......................................................................................................................................................................................................................................................

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d) 300cm3 of air at a temperature of 00c and a pressure of 1.0x105 Pa was heated in a sealed container. Assuming the volume of the container remains unchanged, determine the temperature at which the pressure raises to 5x105Pa.

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12 marks

18.

a) Name any two renewable sources of energy

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b) Figure 8, shows a 10kg bag at rest held by a woman at a height of 0.5m from the floor

i) How much work does she do?

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ii) She then lifts it straight up to a height of 2m from the floor. How much work does she do now? .................................................................................................................................................................................................................................................

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iii) In case she lifts the weight from position A to position C (same height as B) but along the path AC, how much work does she do now? Explain your answer.

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c) A catapult is used to fire a stone of mass 50g vertically to a height of 4.05m. At what speed does the stone leave the catapult.

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11 marks

19.

Figure 9 illustrates an experiment in which electrical energy, used to produce a measured rise in temperature of a liquid can be determined.

a)

i) Point out the faults in this arrangement and state how they should be corrected.

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ii) In what ways is the heat lost? What precautions should be taken to reduce the heat loss? ....................................................................................................................................................................................................................................................................

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iii) Why is the rheostat used?

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b) Explain why;

i) The liquid tend to be warmer at the top than at the bottom of the container.

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ii) The temperature will eventually stop rising even though the current is still passing the liquid. ....................................................................................................................................................................................................................................................................

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c) The electric heater put into 500g of oil for 5minutes raises the temperature of oil from 200C to 360C. The metre readings for the power supply are:- Voltmeter=12.0V: ammeter =4.0A. Neglecting the effect of the container and assuming no heat loss, calculate the specific heat capacity of oil.

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12 marks

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