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

Instructions to Candidates

• This paper consists of TWO sections: A and B.
• Answer ALL the questions in sections A and B in the spaces provided.
• ALL working MUST be clearly shown.
• Mathematical tables and non-programmable silent electronic calculators may be used.y

SECTION A: (25 Marks)
Answer all the questions in this section in the spaces provide

1. State the reading on the Vernier caliper shown in fig. 1 below. [1]
   
2. A girl stands inside a lift on the second floor of an 18 storey building. If the lift is ascending upwards at an acceleration of 3ms^-2 and she weighs 60kg, determine the reaction of the lift at the girl’s feet. [3]
3. Figure 2 below represents a car hydraulic braking system.
   
   Use the information given in the diagram above to answer questions 3(a) and 3(b).
   1. State one property the fluid should have.     [1]
   2. Explain briefly how the system operates.       [3]
4. Figure 3 below shows a machine being used to raise a load. Use the information given in the figure to answer questions 4(a) and 4(b) below.
   
   Fig 3
   1. Determine the velocity ratio (V.R) of the machine. [1]
   2. If a load of 800N is raised by applying an effort of 272N, determine the efficiency of the machine. [3]
5. What happens to the motion of smoke particles in the smoke cell experiment when the setup is moved from an environment at 27°c to an environment at 47°C? [1]
6. State Charles’s Law. [1]
7. A piece of iron is heated. Explain what happens to its density. [2]
8. Figure 4 below shows two identical beakers A and B. Beaker A contains water at 0°C while B contains water and pieces of ice at 0°C. Both contents have the same mass.
   
                          Fig. 4
   Two identical metal blocks are removed from the same hot furnace and dropped into each of the beakers. Identify which of the two beakers would experience more evaporation and give a reason for your answer. [2]
9. A force of 7.5N stretches a certain spring by 5.0cm. How much work is done in stretching this spring by 8.0 cm? [3]
10. State the Pascal’s principle of pressure transmission in fluid. [1]
11. Figure 5 below shows a velocity time graph for a car in motion. If the mass of the car is 920kg, determine the maximum kinetic energy acquired for part of the journey shown [2]
    
                                Fig. 5
12. A bullet is fired horizontally at a target, neglecting air resistance, give a reason why the horizontal acceleration of the bullet is zero. [1]

SECTION B ( 55 marks) 

13.  
    1. Figure 6 above shows the velocity time graph of two identical spheres released from the surfaces of two fluids A and B.
       
                            Fig. 6
       1. State with reason, the fluid with a higher viscosity. [2]
       2. Mark on the diagram the terminal velocity on the sphere in each fluid. [1]
    2. Water flows through a horizontal pipe of varying cross-section area as shown in figure 7 below.
       
                                    Fig. 7
       The velocity of water in pipe A is 2m/s
       1. Determine the velocity of water in pipe B. [3]
       2. State two assumptions taken in Bernoulli’s fluid flow. [2]
       3. Explain why a partially inflated balloon released at sea level would become fully inflated at a higher altitude. [2]
14.  
    1. State Boyle’s Law. [1]
    2. The table below shows the results from Boyle’s law experiment.
       

       Pressure (atmospheres)	1.0	1.3	1.5	1.8	2.3	2.6	3.2	3.7
       Length of air column, L(mm)	41.0	30.0	27.5	22.0	18.0	16.0	12.5	11.0
       I/L x 10-2 (mm)-1

       1. Complete the table by filling in the values for the row   ^I/_L x 10^-2 (mm)^-1          [4]
       2. Plot a graph of pressure against ^I/_L          [5]
       3. Estimate the pressure of the air when I/L is zero. [1]
15.  
    1. Define the terms
       1. Inelastic collisions [1]
       2. Momentum [1]
    2. A bullet of mass 20g moving with a velocity of 1000m/s hits stationery antelope of mass 12kg. The bullet imbeds and the two move in one direction. Calculate its final velocity [2]
    3. Block of mass 200g rests on a rough horizontal table. A force of 0.6N pulls the block so that it moves with a constant acceleration of 1m/s² calculate
       1. The time it takes to travel a distance of 200m      [2]
       2. The frictional force between the block and the table      [2]
       3. The coefficient of kinetic friction between the two forces       [2]
       4. A part from the normal reaction and frictional force, name any other force       [2]
16.  
    1. Define the term latent heat [1]
    2. Figure 8 below shows a block of ice with two heavy weights hanging such that the copper wire / string connecting them passes over the block of ice.
       
                                          Fig. 8
       1. It is observed that the wire gradually cuts its way through the ice block, but leaves it as one piece. Explain [5]
       2. What change would be observed if the copper wire used in the experiment was replaced by a cotton thread? Explain your answer.              [2]
    3. 3kg hot water was added to 9kg of water at 10°C and the resulting temperature was 20°C. Ignoring heat gained by the container, determine the initial temperature of the hot water. (Specific heat capacity of water = 4200J/KgK).             [3]
    4. What is the operating resistance of an electric heater rated 90W, 240V?             [3]
17.  
    1.  
       1. State the principle of moments.               [1]
       2. A uniform metre rule has a mass of 300g and is pivoted freely at the 0 cm mark. Determine the force which should be applied vertically upwards at the 55cm mark to maintain the ruler horizontally.             [3]
    2. Figure 9 below shows a piece of tape pulled through a ticker – timer by a trolley down an inclined plane. The frequency of the ticker-timer is 100Hz.
       
                                                         Fig. 9
       1. Find the time between two dots.             [1]
       2. Determine the average velocity of the trolley between Y and P.               [3]

MARKING SCHEME

1. Main scale reading    =   8.30 cm +
   Vernier scale reading =  0.08 cm
                                          8.38 cm✔ 1
2. Resultant force F = Reaction – weight ✔ 1
                            F + W =R
                            R = ma + mg 1 = m(a+g)
                               = 60 kg (10ms^-2 + 3ms ^-2) = 780N✔ 1
3.  
   1.  
      • be incompressible✔
      • Not corrosive✔
      • Have low freezing point and high boiling point
   2. The force applied on the foot pedal exerts pressure on the master cylinder ✔ 1.The pressure isTransmitted by the brake fluid to the slave cylinder✔ 1. This causes the slave cylinder to open the brake shoe and hence the brake lining presses the drum✔ 1. The rotation of the wheel is thus resisted.
4.  
   1. V.R = 6 ✔ 1
   2. M.A =  800  = 2.941 ✔ 1
                  272
      E = M.A  x 100% = 2.941 x100✔ 1 = 49.017 %✔ 1
             V.R                     6
5. The motion of the particles increase ✔ 1
6. The volume of a fixed mass of gas is directly proportional to its absolute temperature if the pressure is kept constant. ✔ 1
7.  
   • Its density reduces ✔ 1
   • Because during expansion the volume increases and its mass remains constant. ✔
8.  
   • A✔ 1
   • In B some heat will be required to melt the ice hence the temperature will be slightly lower.✔
9. 7.5 N → 5cm          
      ?    →  8cm                         
   7.5 × 8 = 12.0 N✔ 1
     5
    Work done = ½ force extension ✔ 1
                       = ½ × 12 × ⁸/₁₀₀ = 0.48 J✔ 1
10. Pressure applied at one point of a liquid is transmitted equally to all other parts of enclosed liquid ✔
11. K.E = ½ MV² 
    = ½ × 920 × 30² ✔ 1 = 414000J ✔ 1
12. Because the horizontal force acting on the bullet is zero. ✔ 1
13.  
    1.  
       1.  
          • A, has higher viscosity. ✔ 1
          • Because in fluid A a lower terminal velocity is registered due to the higher resistance of the fluid molecules to the movement of the sphere through it. ✔ 1
       2.  
          
    2.  
       1. A₁ V₁ = A₂V₂ ✔ 1
          100 x 2 = 60 V₂ ✔
          V₂ = 200 = 3.33 m/s✔ 1
                   60
       2.  
          • Liquid is non –viscous ✔ 1
          • Liquid is incompressible ✔ 1
       3.  
          • As the ball rises, the atmospheric pressure on the ball reduces. ✔ 1
          • At higher altitude the pressure outside is relatively lower, thus the pressure inside the balloon exceeds the one outside causing it to become fully inflated. ✔ 1
14.  
    1. The pressure of a fixed mass of a gas is inversely proportional to its volume, provided thetemperature is kept constant. ✔ 1
    2.  
       1. .
          

          Pressure (atmospheres)	1.0	1.3	1.5	1.8	2.3	2.6	3.2	3.7
          Length of air column, L(mm)	41.0	30.0	27.5	22.0	18.0	16.0	12.5	11.0
          I/L x 10-2 (mm)-1	2.44✔½	3.33✔½	3.64✔½	4.55✔½	5.56✔½	6.25✔½	8.00✔½	9.10✔½

       2.  
          
          Check graph paper
       3. Pressure of the air column when the length, L of air is zero
          P= 0 atmospheres ✔ 1
15.  
    1.  
       1. is the collision✔ in which objects combine after impact and move in one direction or become Stationery
       2. Momentum is the ✔quantity of motion of a body given by the product of mass and velocity
    2. Momentum before impact = collision after impact
       (  20   × 100) + (12×0) = (12 + 120 )v
        1000                                       1000
       20 = 12.02 v
       v = 1.66 m / s
    3.  
       1. S = ut + ½ at²
          t = √²/_sa
            =  ✔
            = 20s
       2. F = ma
             = 0.2 ×1
             = 0.2 N ✔
          Fr= 0.6 − 0.2
              = 0.4 N ✔
       3. μ = ^Fr/_R
          = 0.4
             0.2 ✔
           =2 ✔
       4. When it is pulled there is tensional force on the string✔
16.  
    1. The quantity of heat required to change the state of a given mass of substance without change in Temperature. ✔ 1
    2.  
       1. Because of the hanging weights, the wire exerts pressure on the ice beneath✔ 1 it and therefore makes it melt at a temperature lower that its melting point. ✔ 1. Once the ice has melted, the water formed flows over the wire and immediately solidifies since it is no longer under pressure✔ 1
          As it solidifies, the latent heat of fusion is released and conducted by the copper wire to melt the ice below the wire ✔ 1. The process continues until the wire cuts through leaving the block intact✔ 1.
       2. The cotton thread would not cut through the ice at all ✔1. This is because cotton is a poor conductor of heat✔ 1 hence it would not conduct the latent heat of fusion released by the Solidifying ice to melt the ice below.
    3. Heat lost by hot water = Heat gained by cold water
       MhC Δθ = McC Δθ₂ ✔ 1
       3 (θ − 20) = 9 (20 − 10) ✔ 1
       θ − 20 = 30
       θ = 5°C✔
    4. P= V² ✔ 1            R = V² =  240 x 240V ✔ 1
             R                           P            90 w
       = 640 Ω ✔ 1
17.  
    1.  
       1. at equilibrium, the sum of clockwise moments a point is equal to the sum of the anti-clockwise moments about the same point. ✔1
       2. Clockwise moments = Anti-clockwise moment✔1
          W x 50cm = 55 x F ✔1
          F= 3N ⁵⁰/₅₅ = 2.73N✔1
    2.  
       1. T = ¹/_f = ¹/₁₀₀Hz = 0.01 s ✔1
       2. Average velocity = total distance    ✔1
                                            total time
                                    =          40           ✔1
                                         12 × 0.01s
                                   = 33.33cm/s  ✔1 or
                                   = 0.33m/s