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PHYSICS PAPER 1
May 2018
Time: 2 HOURS
ALLIANCE HIGH SCHOOL
PreTrial Exams
INSTRUCTIONS TO CANDIDATES
 Mathematical tables and nonprogrammable calculators may be used
 This paper consists of section A and section B.
 Attempt all the questions in the spaces provided.
SECTION A (25 MARKS)
 Figure 1. shows a glass beaker of cross sectional area 10.5 cm^{2}
When the metal bllock of mass 200g is immersed into the water, the level of water rises by 3.5 cm, determing the density of the metal block in S.I units. (3 marks)^{}  The figure 2 shows air flowing through a pipe of nonuniform cross sectional area. Two tubes A and B are dipped into the liquid as shown.
 Indicate the level of the liquid in tubes A and B. (1 mk)
 Explain your answer in part (a) above. (1 mk)
 A motor cyclist wears a helmet that has inside lined with sponge. Explain how this minimizes injuries to the motorists head if involved in an accident. (2 mks)
 A balloon is filled with helium gas and then released. It is observed to rise in air up to a certain height and stops. State a reason why the balloon stops rising. (1 mk)
 Figure 3 below shows two pieces of cork fixed on a polished and a dull surface with wax.
State and explain the observation made, when the heater is switched on for a short time given that the heater is equidistant from the two surfaces. (2 mks)  The air pressure at the base of a mountain is 70cmHg while at the top of the mountain is 50cmHg. Given that the average density of air is130kg/m^{3 }and the density of mercury is 13600kg/m^{3}, determine the height of the mountain. (3 mks)
 Figure 4 shows a stone of weight W placed on a plane that is inclined at an angle θ
 Indicate with arrows, two other forces acting on the stone. (2 marks)
 State the reason why it is easier to separate water into drops than to separate a solid into smaller pieces. (1 mk)
 Figure 5 shows a uniform beam held at equilibrium.
Determine the weight of the beam. (3 marks)  Figure 6 shows a glass containing a piece of ice placed on a bench.
State the change on the stability of the glass when temperature increases. (1 mark)
 State the reason why radiation is the fastest mode of heat transfer. (1 mk)
 Explain how sensitivity of a thermometer can be improved. (1 mk)
 Figure 7 shows a mass of 12g suspended on a set of 6 identical springs. When the mass was hanged on spring A, it extended by 6cm.
Determine the extension of the combination shown if each spring and rod has negligible weight. (2 mks)  Sketch a graph of volume of a fixed mass of a gas against pressure on the axes below. (1 mk)
 State the law of inertia. (1 mk)
 The figure below shows a hydraulic lift that is operated by rolling a ball of mass 50kg from the top of a cliff 20m high with a horizontal velocity of 20m/s. On reaching the ground, it hit piston X of a hydraulic lift. Piston Y has a weight of 25200N on it.
Given that the tap was open when the ball struck piston x.
Determine: The time taken by the ball to strike Piston X (3 marks)
 The distance from the foot of the cliff to where the ball strikes piston x. (2 mks)
 The vertical velocity at which it struck X. (2 mks)
 The force with which the ball struck X given that the time of impact is 0.02s and that the ball comes to rest. (2 mks)
 The distance moved by the 25200N load given that the level of liquid in both arms was initially the same. (2 marks)
 The graph shows the relationship between volume and temperature for an experiment.

 What was the volume of the gas at 0^{o}C? (1 mark)
 At what temperature would the volume of the gas be zero. (1 mark)
 Explain why the temperature in part (ii) above cannot be achieved. (1 mark)
 A wooden block of mass 50g floats with 20% of its voulme above the water surface and kept in place by a string as shown below. The tension in the string is 0.06N
Determine: The upthrust experienced by the object. (2 marks)
 The volume of the displaced. (2 mks)
 The density of the object. (3 mks)

 Figure 11 shows a car of mass m, moving along a curved part of the road with a constant speed.

 Explain why the car is more likely to skid at B than at A. (2 mks)
 If the radius of the path at B is 200m and the car has a mass of 5000kg, determine the maximum speed the car can be driven while at B to avoid skidding if the coefficient of friction between the road and the tires is 0.3 (3 marks)
 A string of length 70cm is used to whirl a stone of mass 0.5 kg in a circle of a vertical plane at 5 rev/s. Determine:
 The period. (2 marks)
 The angular velocity. (3 marks)
 The figure 12 shows a flywheel of radius 14cm suspended about a horizontal axis through its centre so that it can rotate freely about the axis. A thread is wrapped round the wheen and mass attached to its loose end so as to hang at a point 1.25 m above the ground.
When the mass is released, it accelerates at 0.28m/s^{2}. Determine the angular velocity of the wheel just before the mass strikes the ground. (4 marks)


 Define specific latent heat of vaporization. (1 mk)
 Water of mass 100g and temperature 10^{o}C is put in a copper calorimeter of mass 40g. Steam from boiler at normal pressure is passed into the calorimeter for some time. The total mass of the calorimeter and contents is 143g, the final temperature of the contents is measured and is T.
Determine: Heat lost by steam on condensing to water. (2 marks)
 Heat lost by condensed water. (2 mks)
 Heat gained by the calorimeter and the cold water (3 mks)
 The value of T (2 mks)
(Take specific heat capacity of water = 4200J/kg/k and copper = 900j/kg/k. Specific latent heat of vaporization of steam = 2.26 x 10^{6} J/kg)

 The figure 13 shows a pulley system used for lifting loads.
 What is the velocity ratio of the pulley system? (1 mk)
 If it's efficiency is 80%, determine the mechanical advantage. (2 mks)
 If the load is 300N, determine the effort. (2 marks)
 Derive an expression for the velocity ration of the wheel and axle machine if the wheel has a radious of R and axle has a radius of r. (3 marks)
 The figure 13 shows a pulley system used for lifting loads.