3. DENSITY FORMULA
Density = Mass m
Volume v
Units g/ml, g/cm3, g/cc
Remember 1 ml = 1 cm3 = 1 cc

4. C

7. Archimedes' Principle is
named after
“ARCHIMEDE’S OF
SYRACUSE "who first
discovered this law

8. upthrust
Archimedes’
Principle

12. The buoyant force acting on an
object depends upon two factors:
The volume of the body
immersed i.e. volume of the fluid
displaced ,or
density of the fluid

13. APPARENT LOSS IN WEIGHT
 = True weight-weight of the body immersed
in a fluid (=buoyant force)
 = w1-w2

14. BUOYANT FORCE
 =apparent loss in weight-true weight(w1)

16. VERIFYING ARCHIMEDES’ PRINCIPLE
 Take an Eureka can and fill it up to its spout.
Take a stone and suspend it with the hook of
the spring balance.Note the weight of stone
in air.Let it be w1.
 Now immerse the stone inside water in the
Eureka can.the water overflows through the
can.Collect this overflowing water in the
beaker. Now also note the reading in the
spring balance.Let it be w2

17.  This w2 will be less than w1 due to upthrust
provided by water.Apparent loss in weight
due to upthrust will be (w1-w2)
 Measure the weight of water collected in the
beaker , which in fact is the weight of water
displaced by the stone .
 On comparing we will found that the loss in
weight (w1-w2 )is equal to the weight of the
water displaced by the stone.Hence the
Archimedes’principle is verified.
upthrust
apparent loss in weight is equal to
the weight of the fluid displaced by
the immersed part of the body

25. WHERE WILL THEY “FLOAT?”
salt water
density=
1.2 g/cc
fresh water
density=
1.0 g/cc
oil
density=
0.9 g/cc
Object A: density= 0.8 g/cc
Object B:density= 0.95 g/cc
Object C:density = 1.1 g/cc
Object D:density= 1.3 g/cc
Object E:density= 4.0 g/cc

28. A ship is hollow at the
bottom because of which its
average density is lees than
that of water so the ship is
able to displace water equal
to its weight and hence it

31.  If the submarine has to come up,the tanks
are emptied out ,so the weight of the
submarine decreases in comparison to the
weight of the water displaced and the
submarine rises up to the surface

32. THE FISHES
 Some species of fishes have swim bladder.
When fishes want to rise they fill this bladder
with gases diffused from their own body.
Thus becoming lighter and to go down they
empty their bladder thereby increasing their
density and hence manage to sink

34.  Hydrogen and Helium filled balloons and hot
air balloons tend to move upwards because
the density of hydrogen is about 1/4th of the
air. The upward force is more than the
downward force of the balloon and hence it
rises upwards till the density of both
becomes same