Essay [60 marks]
Answer eight questions in all; five questions from Part I and three questions from Part II.
Part I [15 marks]
Answer any five questions from this part.
All questions carry equal marks.

  1. (a) What is a projectile? [1 mark]
    (b) Give the reason why the horizontal component of the velocity of a projectile remains the same at every point of its
    flight [ 3marks ]
    .
  2. A body is projected at an angle of 30° to the horizontal with a velocity of 150 ms-1.
    Calculate the time it takes to reach the greatest height. (Take g = 10 ms-2; and neglect air resistance) [ 4marks]
  3. A wire of length 2.00 m and radius 1.0 mm is stretched by 25.0 mm on application of a force of 103N. Calculate
    the Young’s modulus for the wire [4 marks]
  4. State three ways of increasing the rate of cooling of a cup of hot tea. [4 marks ]
  5. State the dimensions of:
    a. impulse; b. acceleration; c. work [ 4marks]
  6. A projectile is fired with a velocity of 20 m s-1 at an angle of 40° to the horizontal. Determine the components of
    the velocity of the projectile at its maximum height. [4 marks ]
  7. State three different materials that can be used to demonstrate Brownian motion. [4 marks ]
    8.(ai) An electron enters perpendicularly into a uniform magnetic field which has a flux density of 0.12 T. This
    results in a magnetic force of 9.6 x 10-12 N on the electron. Calculate the speed of the electron as it enters the
    magnetic field. [ e = 1.6 x 10-19 C] [4 marks]
    Part II [45 marks]
    Answer three questions from this part.
    All questions carry equal marks.
  8. (a) (i) Define uniform acceleration. [2 marks]
    (ii) Write an equation, that relates linear velocity, angular velocity and radius of path in circular motion. [1 mark]
    (b) Two forces 30N and 40N act at right angles to each other. Determine by scale drawing the magnitude and
    direction of the resultant force, using a scale of 1 cm to 5 N. [4 marks ]
    (c) Explain why ships are usually refilled with sand and water after they have been emptied of their cargo. [3 marks]
    (d) A crate of drinks of mass 20 kg is placed on a plane inclined at 30° to the horizontal. If the crate slides down with
    a constant speed, calculate the:
    i. co-efficient of kinetic friction;
    ii. magnitude of the frictional force acting on the crate.
    [ g = 10 ms-2 ] [5 marks]
    10..(a) Define specific latent heat of vaporization. [2 marks]
    (b) (i) What are renewable energy sources? [2 marks]
    (ii) List four renewable energy sources. [2 marks]
    (c) Explain why tomatoes keep longer when kept in a moist jute bag in a clay pot. [3 marks]
    (d) A box has a volume of 0.28m3 and is 70% filled with iron filings at 25°C.
    Calculate the:
    i. total mass of the iron filings;
    ii. energy required to melt 10% of the iron filings.
    [Density of iron = 8.00 x 103 kg m-3; Specific latent heat of fusion of iron = 1.38 x 105J kg-1 Specific heat capacity
    of iron = 460 J kg-1K-1; Melting point of iron = 1500°C [6 marks]
  9. (a) (i) What is resonance? [2 marks]
    (ii) State two examples of resonance. [2 marks]
    (iii) Differentiate between loudness and intensity of sound. [1 marks]
    (b) A sample of radioactive substance was found to be left with 1/32nd of its initial count rate after 110 years.
    Calculate its decay constant. [4 marks]
    (c) A diverging lens of focal length 18.0 m is used to view a shark that is 90.0 m away from the lens. If the image
    formed is 1.0 m long, calculate the:
    i. image distance;
    ii. length of the shark. [6 marks]
    (c) i. Why are γ-rays not deflected by electromagnetic fields? 3 marks ]
    ii. State two properties of gamma rays that make them suitable for sterilizing medical equipment. [2 marks]
  10. (a) (i) Define the coulomb. [2 marks]
    (ii) Define resistance. [1 marks]
    (b) State the three effects of an electric current. [3 marks]
    (c) State the standard international colour convention for the insulating material covering the following electrical
    wires in a three-pin plug:
    (i) live;
    (ii) neutral;
    (iii) earth. [6 marks]
    (d)A water melon of mass 5.0 kg is suspended on a uniform rod of mass 4.0 kg and 4.0 m long as illustrated in the
    diagram above. If the rod is in equilibrium by the action of the force between the charges + q and – q, calculate the:
    i. anticlockwise moment;
    ii. value of q.
    [ g = 10 ms-2 ] [6 marks]
    (e) Define nucleon number. [2 marks]