4. (a) Give two practical examples where impulse and momentum play an important role.
(b) (i) Distinguish between elastic collisions and inelastic collisions.
(ii) A box of mass 50 kg is raised vertically with a uniform acceleration ‘a’ when a force of 700 N is acting in a rope. Calculate the uniform acceleration ‘a’.
(c) (i) State Newton’s second law of motion.
(ii) Sand falls gently at a constant rate of 50 g/s onto a horizontal belt moving steadily at 40 cm/s. Find the force in newtons exerted by the sand on the belt. State any assumptions made in your calculation.
(b) (i) Distinguish between absolute velocity and relative velocity.
(ii) Wind is blowing 30° west of north at 20 km/hour. A bird is flying in the wind and its velocity relative to the ground is 90 km/hour at 75° west of north. Calculate the velocity and direction of the bird.
(c) (i) Define the coefficient of dynamic friction.
(ii) A body of mass 40 kg is placed in a straight track sloping at an angle of 45° to the horizontal. If the body is held from slipping by friction, calculate the normal reaction and the force of friction.
(ii) Give two effects of beta (β) particle on the nucleus of an atom.
(b) (i)Define the term isotope of an element.
(c) (i)How would you test whether a car battery needs recharging? (Give three points).
(ii) Two resistors each of 5 Ω Are connected in parallel across the same battery of e.m.f. 5 V and negligible internal resistance. If the battery is fully charged and then discharged within 20 hours, calculate the storage capacity of the battery.