Page 99 - Physics

Density and relative density

(b) The mass of a stone is measured monitor the water in a fi sh tank to
to be 410 g. The stone is then ensure the proper amount of salt?
immersed in water contained 10. One day, two students went to a
in a cylinder graduated in cm . supermarket to buy some home
3
The water level increases as
shown in Figure 4.15. What is supplies. They were surprises to
the density of the stone? fi nd two pockets of milk written
‘skimmed milk’ and the other ‘semi-
skimmed milk’. They wandered
whether the two products are the
similar. To clear they are doubt they
decided to determine the relative
density of each product. As a form
Measuring
Cylinder one student, what do you think was
String their conclusion.

Water

Stone

Figure 4.15

What is the density of the stone?
(Note: 1 ml = 1 cm ).
3
5. The length of one side of a metal
cube is 4.22 cm and its mass is 65.8 g.
What is the density of the cube? (a) Fresh milk (b) Skimmed milk
6. If the volume of an object is increased Figure 4.16
while its mass is held constant, what 11. The diametre of a solid metal sphere
happens to its density? is measured using a micrometre
7. If a 200 g solid lead ball is placed in screw gauge. Figure 4.17 shows an
a eureka can fi lled with water, what enlarged shaft of the micrometre
volume of water will overfl ow? Take screw gauge when taking the
the density of lead as 11.3 g/cm . measurement.
3
8. A small quantity of powdered
charcoal is placed in a 100 cm 3
density bottle and the total mass is
measured to be 255 g. If the mass
of empty density bottle is 20 g and
when the bottle is fi lled with water, Figure 4.17
the total mass is 289 g, what is the
density of the powdered charcoal? If the mass of the sphere is 0.450 g.
9. Fishes are very sensitive to a change What is the density of the metal used
to make the sphere?
in salinity. Explain how you can

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Physics Form 1 Final.indd 93 16/10/2024 20:56