DENSITY
1 A block of iron is
much heavier than a block of wood of the same size. Which has the greater
density, iron or wood?
2 lf a block of a
material has a volume of 6 m3 and a mass of 48 kg, what is its
density?
3 What is the volume
of 72 g of copper? Density of copper = 9 g/cm3.
4 What is the mass
of 4 m3 of soil? Density of soil = 2 g/cm3
5 Water has a
density of 1 g/cm3 (1000 kg/m3). Which of the following
will float in water?
Ice
(920 kg/m3); wood (0.6 g/cm3); carbon (2300 kg/m3).
6 (a) What two forces
act on an object immersed in a liquid?
(b)
If the object sinks which is the bigger of these two forces?
7 When an object floats in a liquid, what is
the upthrust on it equal to?
8 What is the
upthrust in newtons on a 50 kg lump of wood floating in water? (g = 10 N/kg)
9 A 1000 kg boat
floats in water. What is the weight of water displaced by the boat?
10 A block has a mass of 5 kg in air and an
apparent mass of 4.5 kg in water.
(a) What is
the loss in weight of the block?
(b) What is
the weight of water displaced?
(c)
What is the volume of the block?
(d) What is
the density of the block?
11 The same block is
now immersed in brine of density 1100 kg/m3.
(a) What is
the upthrust on it?
(b) What is
its weight in brine?
12 A balloon filled with hydrogen will float in
air but when it is burst the rubber of the balloon will fall to the ground.
Why?
13 If a lump of
plasticine is stuck to the hydrometer in diagram A, what will happen to the
hydrometer?
14 Why should you put your head as far back in
the water as you can if you are trying to float?
15 A lump of iron will
sink in water but if you make it into a hollow watertight ball it will float.
Why?
