Physics paper 1 20120918Q
Time: 2 hours
CLASS………………….…. CLASS NO………. DATE…………………………
- This paper consists of two SECTIONS A and B.
- Answer all the questions in the two sections in the spaces provided.
- ALL working MUST be clearly shown.
- Mathematical tables and electronic calculators may be used.
FOR EXAMINER’S USE ONLY
SECTION A – (25 MARKS)
1. State the contact force that opposes the motion of a stone initially at rest, as it falls through air from a tall building. (1mk)
2. When the temperature of a gas in a closed container is raised, the pressure of the gas increases. Explain how the molecules of the gas cause the increase in pressure. (2mks)
3. The figure shows a small match box floating on water in a basin. X and Y are two points near the matchbox.
When a hot metal is dipped into the water at point X, the matchbox is observed to move towards Y. Explain this observation. (2mks)
4. A trolley starts from rest and accelerates uniformly in a straight line. After 3 seconds it is 9m from the starting point. Determine the acceleration of the trolley. (3mks)
5. The figure below shows a uniform stone of mass 10kg and length 30cm lying on a table. It hangs over the edge of the table by 10cm. Use the figure to answer questions a and b.
a. Show on the stone two forces acting on it. (1mk)
b. Determine the minimum force that can be applied on the stone to make it turn about the edge of the bench. (2mks)
6. When a liquid is heated in a glass flask, its level at first falls, then rises. Explain this observation. (2mks)
7. The figure below shows a sheet of paper rolled into a tube.
When a fast steam of air is blown into the tube as shown in the diagram the paper tube collapses. Explain the observation.
8. The weight of a solid in air is 5.0N. When it is fully immersed in a liquid of density 800kg/m3, its weight is 4.04N.
a. the upthrust in the liquid. (1mk)
b. the volume of the solid. (3mks)
c. the density of the solid. (2mks)
9. State what is meant by absolute zero temperature (zero Kelvin or – 273°C).
10. A turn table of radius 12cm is rotating at 33 revolutions per second. Determine the linear speed of a point on the circumference of the turntable. (3mks)
SECTION B – 55 MARKS
11.a. A cyclist initially at rest moved down a hill without pedaling. He applied brakes and eventually stopped. State the energy changes as the cyclist moved down the hill. (1mk)
b. The figure below shows a mass of 60kg being pulled from point P to point Q, with a force of 400N parallel to an inclined plane. The distance, between P and Q is 25m. In being moved from P to Q the mass is raised through a vertical height of 10m.
i. Determine the work done:
I by the force (2mks)
II on the mass (2mks)
III to overcome friction (2mks)
ii. Determine the efficiency of the inclined plane. (2mks)
iii. Determine one method of improving the efficiency of an inclined plane. (1mk)
12. Brownian motion of smoke particles can be studied by using the apparatus shown in the figure below. To observe the motion, some smoke is enclosed in the smoke cell and then observed through the microscope.
a. Explain the role of the smoke particles, lens and microscope in the experiment.
i. Smoke particles (2mks)
ii. Lens (2mks)
iii. Microscope (2mks)
b. State and explain the nature of the observed motion of the smoke particles.
c. State what will be observed about the motion of the smoke particles if the temperature surrounding the smoke cell is raised slightly. (1mk)
13.a. Define specific latent heat of fusion of a substance. (1mk)
b. Water of mass 200g at a temperature of 60°C is put in a well lagged copper calorimeter of mass 80g. A piece of ice at 0°C and mass 20g is placed in the calorimeter and the mixture stirred gently until all the ice melts. The final temperature T, of the mixture is then measured.
i. the heat absorbed by the melting ice at 0°C. (2mks)
ii. the heat absorbed by the melted ice (water) to rise to temperature T. (answer may be given in terms of T). (2mks)
iii. the heat lost by the warm water and the calorimeter (answer may be given in terms of T). (2mks)
iv. the final temperature T of the mixture. (specific latent heat of fusion of ice = 334000Jkg -1 specific heat capacity of water = 4200Jkg -1 K -1, specific heat capacity of copper = 900J kg -1 K -1) (4mks)
v. Write down two assumptions made during the experiment. (2mks)
14.a.i. State the pressure law of an ideal gas. (1mk)
b. The pressure, P, of a fixed mass of a gas at a constant temperature T = 300k
is varied continuously. The corresponding values of P and the volume V of the gas are shown in the table below.
|Pressure P (x105pa)||2.00||2.50||3.00||3.50||4.00||4.50|
i. Plot a graph of P – y axis against 1/v. (7mks)
ii. From the graph determine R given that PV = 2RT. (3mks)
15.a. Distinguish between solid and liquid states of matter in terms of intermolecular forces. (1mk)
b. In an experiment to estimate the diameter of an oil molecule, an oil drop of diameter 0.05cm spreads over a circular patch whose diameter is 20cm.
i. the volume of the oil drop. (2mks)
ii. the area of the patch covered by the oil. (2mks)
iii. the diameter of the oil molecule. (3mks)
i. any assumption made in (b) (iii) above. (1mk)
ii. two possible source of errors in this experiment. (2mks)
(Get marking scheme beneath)
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