PHYSICS QUIZ 4 O'LEVEL

PHYSICS QUIZ 4 O'LEVEL

1. (a) Explain the effect observed when kerosene is mixed with water in a beaker. Give a reason to support your answer.
(b) A liquid mixture of water and alcohol has a density of 900 kg/m'. Find the mass of alcohol in one litre of the mixture.

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2. (a) How can a metre rule be balanced on a knife-edge?
(b) Two spheres of mass 3.0kg and 2.0kg are joined by a light rod so that their centres are 0.45m apart. Locate the centre of gravity of the system.

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3. (a) Define velocity ration and mechanical advantage of a system.
(b) A screw jack has a pitch of 1.0mm and is worked by the arm of length 70mm. If its efficiency is 40% what load can be raised by an effort of 10N?

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4. A diver working at the bottom of a freshwater lake 30 metres deep releases a stream of air bubbles, each of volume 0.00005m', Assuming the temperature of water to be uniform and that the atmospheric pressure at the surface is 100,000N/m2.
(a) Find the volume of each bubble when it just reaches the surface.
(b) Why does the bubble grow as it ascends up the lake?

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5. (a) What does it mean by the coefficient of linear expansion?
(b) A brass rod is 1.000m long at 0°C. A steel rod is 1.0mm longer at the same temperature. At what temperature are they the same length?

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