21. A swinging pendulum between the rest position and its maximum displacement possesses A. kinetic energy only B. potential energy only C. gravitational energy only D. both kinetic and potential energy. E. inertia kinetic and potential energy 22. A stationary object of mass 4kg is set in motion by a net force of 50N. If the object attains a speed of 5ms' in time t, calculate the value of t. A. 0.20s B. 0.40s C. 0.63s D. 0,80s E. 0.56s 23. Newton's second law of motion states that A. the force, on a body is inversely proportional to its mas B. when two or more bodies act upon one another, their total momentum remains constant when external forces are acting on the body. C. the time rate of change of linear momentum of a body is proportional to the impressed force and takes place in the direction in which the force acts. D. the force acting on a body in motion s proportional to its kinetic energy. E. the force acting on two bodies not in contact is proportional to their masses and inversely to distance of separation 24. A net force of magnitude .6N acts on a body of mass 40g, initially at rest. Calculate the magnitude of the resulting acceleration. A. 90ms B. 60ms C. 30ms D. 15ms E. 27ms 25. An inelastic collision takes place between balls of known masses. Just before collision, one of the balls is moving with a velocity while the other is stationary. Which of the following physical quantities can be determined from the information given? A. Speed of ach of the balls after collision B. kinetic energy of each of the balls after collision C. total momentum of the two balls after collision D. mutual forces exerted by the balls E. the shape of the balls 26. The tendency of a boy to remain at rest when a force is applied to it is called A. impulse B. momentum C. inertia D. friction E. weight 27. Which of the following explains the concave meniscus of water in a glass tube? A. the adhesion between water and glass is greater than the cohesion between water molecules B. the cohesion between water molecules is greater than the adhesion between glass and water C. the molecules of water near the glass are moving faster than the molecules in other parts D. the weight of the water pulls the central part of the surface down. E. th galss is at a different temperature than the water due to its conductivity 28. Which of the following will not lower the surface tension of water? B. Methylated spirit C. Soap D. Grease A. Detergent calcium carbonate E. 29. The odour of leaking gas is perceived at a distance from the source. This is possible by the process of A. sublimation B. diffusion C. osmosis D. evaporationE. regelation