## Physics Paper 1 Questions and Answers - Kapsabet Pre Mock Exams 2021/2022

PHYSICS
PAPER 1

INSTRUCTIONS TO CANDIDATES: • Answer all the questions in the spaces provided.
• The paper consists of sections A and B.
• All workings must be clearly shown.
• Mathematical tables and electronic calculators may be used.

SECTION A 25 MARKS
Answer all questions in this section

1. The figure below shows a vernier caliper scale. If the vernier calipers used had a zero error of -0.05cm. What is the actual reading of the scale.? ( 2mks)
2. A body is projected vertically upwards from the top of a cliff. Assuming that it lands at the base of the cliff. Sketch the velocity time graph of the motion. . (2mks)
3. The stability of a body can be increased by increasing the base area and lowering its centre of gravity. State one way of lowering its centre of gravity. . (1mk)
4. When a mercury thermometer is used to measure the temperature of hot water, it is observed that the mercury level first drops before beginning to rise. Explain. . (2mks)
5. The figure below shows a machine being used to raise a load. Use the information given in the figure to answer questions below. 1. Determine the velocity ratio (V.R) of the machine. . (1 mark)
2. If a load of 800N is raised by applying an effort of 272N, determine the efficiency of the machine. . (3 markS)
3. Name the transducer that is used to convert the following form of energies.
1. Electrical to sound. . (1 mark)
2. Electrical to kinetic. . (1 mark)
6. Using the idea of particles, explain why the pressure inside the tyre is increased when it is pumped up (2mks)
7. A trolley of mass 1.5kg moving with a velocity of 1.2ms-1 collides inelastically with a second trolley of mass 0.5kg moving in the opposite direction with a velocity of 0.2ms-1.
1. What is an inelastic collision? (1mk)
2. Determine the velocity of the trolleys after collision. . (2mks)
8. Give one fact which shows that heat from the sun does not reach the earth surface by convection. . (1mk)
9. Three identical springs each of spring constant 1.5N/m and weight 0.5 N are used to support a load as shown in figure 4 below.
Determine the total extension of the system (3mks) 10. State one reason why mercury is preferred as a barometric liquid and not water . (1mk)
11. Figure 5 below shows a uniform meter rule balancing when a mass of 200g is hung at one end. Determine the tension T in the string (2mks) SECTION B ( 55 MARKS) 1.
1. The figure 6 below shows a stone of mass 450g rotated in a vertical circle at 3 revolutions per second. If the string has a length of 1.5m, determine: 1. The linear velocity (3mks)
2. The tension of the string at position A (3mks)
2.
1. State the law of floatation (1mk)
2. Figure 7 shows a piece of cork held with a light thread attached to the bottom of a beaker. The beaker is filled with water. 1. Indicate and label on the diagram the forces acting on the cork (3mks)
2. Write an expression showing the relationship between the forces (1mk)
3. A solid displaces 8.5cm3 of liquid when floating on a certain liquid and 11.5cm3 when fully submerged in the liquid.If the density of the solid is 0.8g/cm3, determine:-
1. Up thrust on the solid when floating (3mks)
2. Density of the liquid (3mks)
3.
1. The Fig. 8 shows a set-up that may be used to verify Charlesâ law. 1. State the measurements that should be taken in the experiment. (2 marks)
2. Explain how the measurements taken in (i) above may be used to verify Charlesâ law. . (3 marks)
2. A block of ice of mass 40g at 0ÂºC is placed in a calorimeter containing 400g of water at 20ÂºC.Ignoring the heat absorbed by the calorimeter, determine the final temperature of the mixture after all the ice have melted. (Specific latent heat capacity of fusion of ice = 340,000JKg-1 and the specific heat capacity of water = 4200 J/KKg . (4mks)
3. Give a reason why an air bubble increases in volume as it ascends to the surface of the liquid in a boiler. (1 mark)
4. Define the term absolute temperature (1 mark)
4. The figure below shows an inclined plane, a trolley of mass 30kg is pulled up a slope by a force of 100N, parallel to the slope. The trolley moves so that the centre of mass C travels from points A to B. 1. What is the work done on the trolley against the gravitational force in moving from A to B.? (2mks)
2. Determine the work done by the force in moving the trolley from A to B. . (2mks)
3. Determine the efficiency of the system. . (3mks)
4. Determine the work done in overcoming the frictional force. . (1mk)
5. Determine the mechanical advantage of the system. (3mks)
5.
1. State what is meant by an ideal gas (1mrk) .
2. The pressure acting in a gas in a container was changed steadily while the temperature of the gas was maintained constant. The value of volume V of the gas measured for various values of pressure. The graph in the figure A shows the relation between the pressure, P1 and the reciprocal of volume 1/V 1. Suggest how the temperature of the gas could be kept constant (1mk)
2. Given that the relation between the pressure P1 and the volume, V1 of the gas is given by PV = k where k is a constant, use the graph to determine the value of k (3mks)
3. What physical quantity does K represent? (1mk)
4. State one precaution you would take when performing such an experiment (1mk)
3. A gas occupies a volume of 4000 litres temperature of 37ÂºC and normal atmosphere pressure. Determine the new volume of the gas if it is heated at constant pressure to a temperature of 67ÂºC (normal atmosphere pressure P = 1.01 x 105pa) (3mks)
4. A footballer kicks a ball of mass 0.6 kg initially at rest using a force of 720N. If the foot was in contact with the ball for 0.1 seconds, what was the take of speed of the ball? (3mks)
5. An object weighs 1.04N in air, 0.64N when fully immersed in water and 0.72N when fully immersed in a liquid. If the density of water is 1000kgm-3, find the density of the liquid. ( 3 mrks)

MARKING SCHEME

1. Reading indicated = 2.4 +( 8 x 0.01)
= 2.48 cmâ
Error - 0.05cm
2.48 + 0.05 = 2.53cmâ
2. âshape
â area
3. Add weight at bottom/make base heavierâ1
4. Glass expands firstâ increasing internal volume.When mercury is heated it expands faster than glass.
5.
1. V.R = 6 ââ
2. n = ââ
= 49.01% ââ
3.
1. Loudspeaker ââ
2. Motor ââ
6. More air is pumped into the tyre. The number of particles colliding with the walls increases. the increase in the rate of change of momentum , hence the force per unit area increase.â
7.
1. A collision in which objects combine / fuse, losing kinetic energy in the process.
2. Final momentum = Initial momentum(0.5 + 1.5 ) V = (1.5 x 1.2) + (0.5 x 0.2)
2.0V = 1.8 + 0.1
2.0V = 0.9
V = 0.95 m/s
8.
• Convection takes place in air upwards direct due to density effect â1
• Convection requires material medium but the space between the sun and the atmosphere has no material medium.

9. Extention in A=6+1=4.667m Extention in B and C= 6 =2.0m
1.5 2x1.5
Total extension =6.667m

10. Has higher density thus height is reduced in mercury.â Does not vaporize easily.â1 Any one correct

11. Clockwise moments = Anticlockwise momentsâ
W x 0.4 = 2X 0.1â
W = 0.2/0.4
W = 0.5 N
Upward force = downward force.
T = 2 + 0.5
T = 2.5 Nâ
12.
1.
1. V = Ï râ
V = 6Ï x 1.5
= 6 x 3.142 x 1.5
= 28.278m/s â

2. At A
MvÂ²/r = TA+ mg â1

â´ TA = mvÂ²/r â mg =0.45(28.28)/1.5 -0.45x10
=235.43N
13.
1. A floating body displaces its own weight of the fluid in which it floats. â1
2.
1. U = mg + T â1mk
3.
1. Upthrust = weight of solid â1 = âvg
= 800kg/m3 x (115 x 10-6)m3 x 10N/Kgâ = 0.092N â 2. Weight of liquid displaced = upthrust
Ïvg = 0.92 â
Ï = 0.092
(8.5 x 10-6) x 10
=1082 kg/m3
14.
1.
1. length of air column â
temperature of the water â

2. a set of readings of length of air column and corresponding temperature obtained â
a graph of length of air column (volume) against temperature is plotted.
a straight line graph is obtained showing that V Î¬ T â

2. Heat gained by ice=Heat lost by water
(0.04x340000)+(0.04x4200Q)=0.4X4200(20-Q)
13600+168Q=33600-1680Q
Q=10.82 C
3. The pressure acting on the bubble reduces as the depth/height below liquid surface reduces. â
4. Temperature at which a gas will occupy zero volume. â
15.
1. Work done = mgh â (2mks) = 30 Ã10 Ã 10 = 3000J â

2. Work by force 100N = FS (2mks)
= 100 Ã 38.6370
= 3863.70J â

3. Efficiency = â (3mks)
= 77.57% â

4. Work done in overcoming friction = 3863.7 â 3000
= 863.7J â(1mk)

5. V.R= 1/Sin15
=3.864
Efficiency =77.57 =
M.A = 0.7757 Ã3.864
=2.997
16.
1. Is a gas that obeys the gas laws completely.;
2.
1. By carrying out the experiment in a room (where temp. is constant);
2. k =    âP
â 1/v
V3= (4.0 x 105) - (0)
(4.85 x 106) -(0)
= 4 x 10-1
= 4 x 10-1
= 0. 8247 x 10-1
= 8. 247 x 10-2 Nm
3. energy/work done
4. allow air to adjust to room temperature;
17.
1. Vâ/Tâ =   Vâ/Tâ
4000     Vâ
310        340
Vâ =  4000 x 340
310
= 4387 litres

2. MV - MU = Ft
0.6v-0=720x0.1
V=120m/s

3. Upthrust in liquid = 1.04 â 0.72 = 0.32Nâ1
Upthrust in water = 1.04 â 0.64 = 0.40â1
Density of liquid = 1000Kgm-3 x 0.32 = 0.8 x 103 Kgm-3â1
0.40â1