(c) (i) What is meant by least count of a measurement?
(ii) The period of oscillation of a simple pendulum is given by;
whereby 100 vibrations were taken to measure 200 seconds. If the least count for the time and length of a pendulum of 1m are 0.lsec. and Imm respectively, calculate the maximum percentage error in the measurement of g.
2. (a) (i)Mention two characteristics of projectile motion.
(ii) If the range of the projectile is 120m and its time of flight is 4sec, determine the angle of projection and its initial velocity of projection assuming that the acceleration due to gravity g = 10ms-2
(b) (i) State the principles on which the rocket propulsion is based.
(ii) A jet engine on a test bed takes in 40kg of air per second at a velocity of 100ms-1 and burns 0.8kg of fuel per second. After compression and heating the exhaust gases are ejected at 600ms-1 relative to the air craft. Calculate the thrust of the engine.
(c) A boy ties a string around a stone of mass 0.15kg and then whirls it in a horizontal circle at constant speed. If the period of rotation of the stone is 0.4sec and the length between the stone and boy's hand is 0.50m;
(i) Calculate the tension in the string
(ii) State one assumption taken to reach the answer in 3(c)(i).
(b)(i)A thin sheet of aluminium of mass 0.032kg has a length of 0.25m and width of 0.1m. Find its moment of inertia on the plane about an axis parallel to the: length and passing through its centre of mass m.width and passing through the centre of mass m in its own plane.
(ii) A thin circular ring of mass M and radius r is rotating about its axis with constant angular velocity w1. If two objects each of mass m are attached gently at the ring, what will be the angular velocity of the rotating wheel?
(b) (i) Identify two factors on which the coefficient of thermal conductivity of a material depends.
(ii) A brass boiler of base area 1.50 x101m2and thickness of 1.0cm boils water at the rate of 6.0kg/min when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler.