K.C.S.E Physics Q & A - MODEL 2013PP1QN18

K.C.S.E Physics Q & A - MODEL 2013PP1QN18

​(a) Figure 12 shows a weighing balance on which a beaker containing some water is placed. The reading on the balance is 2.80 N. A metal block weighing 2.7 N is suspended from a spring balance

​(i) State what is observed on the spring balance and the weighing balance, as the metal block is gradually lowered into the water.
(I) Observation on spring balance. 
(II) Observation on weighing balance. 
(ii) Explain the observation made on the spring balance in (I).
(iii) When the metal block is fully immersed in the water, the reading on the spring balance is found to be 2.46 N. Determine the:
(I) reading on the weighing balance. 
(II) density of the metal.
(c) Figure 13 shows a hydrometer with a thin stem floating in water in a beaker.

State with a reason what is observed on the hydrometer when the temperature of the water is raised.

answers

(a) (i) (I) - Reading decreases on spring balance;
(II) - Reading on weighing balance increases.
(ii) As the block is lowered, upthust increases; and hence it apparently weighs less;

(c) The hydrometer sinks more;
The density of the water is reduced;