Instructions to candidates;
- Write your Name, Index Number, Class and School in the spaces provided above.
- Sign and Write the date of Examination in the spaces provided above.
- Answer all the questions in Sections A and B in the spaces provided.
- ALL working MUST be clearly shown.
- Silent non programmable electronic calculators may be used.
- This paper consists of 11 printed pages.
- Candidates should answer the questions in English
For Examiners' Use Only
|Section||Question||Maximum score||Candidate's score|
SECTION A: (25 marks)
Attempt all questions in the spaces provided
1. Two students A and B measured the length of a block of wood by placing their eyes at different positions as shown below. Use the diagram to answer questions (1), (ii)
- State the reading as measured by student with the eye at position A. (1 mark)
- State the reading as measured by student with the eye at position B. (1mark)
2. When estimating the size of the oil molecule, lycopodium powder is sprinkled on the oil patch.state the function of the lycopodium powder. (1 mark)
3. The diagram below shows a mercury manometer. Some dry gas is present in the closed space. If the atmospheric pressure is 105kN/m2 and density of mercury 13600kg/ml determine pressure of the gas (take g=10N/kg). (3marks)
4. When a liquid is cooled in a flask its level first rises then falls. Explain this observation. (2 marks)
5. State Hooke's law (1 mark)
6. In the study of brownian motion of air particles. State and explain why smoke particles are used. (2marks)
7. The Figure below shows a test tube with a sliding fitting cork balanced horizontally
Explain why the test tube turns anti-clockwise when it is heated slightly. (2marks)
8. The Figure below shows a uniform metal rod balanced at its centre by different forces.
Determine the value of T. (3marks)
9. A ship carrying load moves from a fresh water to a salty water. Explain what happens to the depth of floating. (2marks)
10. State two precautions to be observed when using a density bottle to measure density of a substance. (2marks)
11. Water flows in a pipe of varying cross-section as shown in the figure below.
Holes A and B develops with time on the pipe.
If the holes have the same dimensions suggest with reason which hole leaks more. (2marks)
12. Explain how the green house get warm. (2 marks)
- In uniform circular motiom, a body is said to be accelerationg yet the speed is constant, Explain this. (1 mark)
- A car goes round a flat circular bend whose radius is 100m at a constant speed of 30m/s. Calculate its acceleration (2 marks)
SECTION B: (55 marks)
Attempt all questions in the spaces provided
- State newton's first law of motion (1mark)
- Distinguish between elastic collision and inelastic collision (1 mark)
- A bullet of mass 0.005kg travelling at a velocity of 100ms' penetrates deeply into a fixed target and is brought to rest in 5 ms. Calculate:
- The distance of penetration into the target (4marks)
- The retardation force exerted on the bullet (3marks)
- The coefficient of friction between the bullet and the target (2marks)
- State the basic assumption in gas laws. (1 mark)
- Carbon dioxide is used to make soft drinks. It is stored in high pressure in cast iron cylinder. The figure below represents the particles in a cylinder of carbon dioxide.
- Describe how the particles of carbon dioxide exert pressure (1 mark)
- The temperature of the gas in the cylinder is now increased.
- State the effect of this on the movement of the carbon dioxide particles (1 mark)
- Explain how this affects the pressure exerted by the gas. (1 mark)
- 20 cm of a gas exerts a pressure of 760 mmHg at 25°C. Determine the temperature of the gas when the pressure increases to 900 mmHg and the volume reduces to 15 cm. (3marks)
- The figure below shows a horizontal tube containing air trapped by mercury thread of length 24cm. The length of the enclosed air column is 15 cm. The atmospheric pressure is 76cm Hg
- State the pressure of the enclosed air in cmHg (1 mark)
- The tube is now held in a vertical position with the open end facing upwards as shown below.
- The pressure of the enclosed air in cmHg.(1 mark)
- The length of the enclosed air column. (2marks)
- State the law of floatation (1 mark)
- The figure below shows two solids P and Q made of the same material and immersed in water.
- State with a reason, which one of the containers experience a greater up thrust (2marks)
- Solid P weighs 12N in air, 2N in water and 4N in another liquid. Determine the density of the other liquid. (density of water =1000kgm-3) (2marks)
- The figure below shows a balloon filled up with air and tied in water such that it is fully submerged.
- If the system is at equilibrium, write an equation relating the three forces acting on the balloon. (1mark)
- State and explain the effect on tension if the water is cooled. (3marks)
- A hydrometer of mass 20g floats in oil of density 0.8gcm-3 with 5cm of its length above the oil. If the cross-section area of the stem is 0.4cm2. Calculate total volume of the hydrometer. (density of water =1000kgm-3)(2 marks)
- The figure below shows a system of lever and a hydraulic press supporting a load of 700N
If r is the radius of the effort piston and R the radius of the effort piston, show that the velocity ratio of the hydraulic press is V.R = (3 marks)
- The cross-section areas of the effort piston and load piston are 0.01m2 and 0.2m? respectively, determine .
- The value of the force F (3 marks)
- The mechanical advantage of the system. (2 marks)
- Velocity ratio of the machine (2 marks)
- Efficiency of the machine (2 marks)
- Define specific latent heat of vaporization (1 mark)
- The bar is placed in a small furnace. Figure below shows how the temperature of a metal bar varies with time t in seconds.
- State what happens to the bar between t = 600 s and 1000 s. (1 mark)
- Explain what effect the energy supplied to the bar has on its molecules between t 0 and 1000 s. (2 marks)
- The mass of the bar is 30g and the specific heat capacity of the metal block is 880 J/(kg K). Calculate the energy supplied to the bar between t= 0 and 600 s. (3 marks)
- Between t-600 s and 1000 s the furnace supplies 30 joules of energy per second to the bar. Calculate the specific latent heat of fusion of the metal bar. (3 marks)