pressure,elevation,pascal's law,equilibrium of floating bodies

1. •Hydrostatic pressure
•Change of pressure with elevation
•Pascal’s law
•Equilibrium of floating bodies
Hydrostatics

2. Problem-1:
A novice scuba diver practicing in a swimming pool takes
enough air from his tank to fully expand his lungs before
abandoning the tank at depth L and swimming to the
surface, failing to exhale during his ascent. At the
surface, the difference p between the external pressure
on him and the air pressure in his lungs is 9.3 kPa. From
what depth does he start? What potentially lethal danger
does he face?

3. Problem-2:
The U-tube in Fig. contains two liquids in static
equilibrium:
Water of density þw =998 kg/m3 is in the right arm,
and oil of unknown density þx is in the left. Measurement
gives
l =135 mm and d = 12.3 mm. What is the density of the
oil??

4. Problem-3:
An 80 kg object lies at the bottom of ocean. If the
volume of object is 4x10^4 cm^3 and the density of
liquid is 1000 kg/m^3. Calculate the force required
to lift it.

5. Problem-4:
In Fig., a block of density 800kg/m^3 floats face
down in a fluid of density 1200 kg/m^3. The block
has a height of H=6.0 m.
(a) By what depth h is the block
submerged?

6. Archimedes’ Principle
(a) The water surrounding the hole in
the water produces a net upward
buoyant force on whatever fills the
hole.
(b) For a stone of the same volume as
the hole, the gravitational force
exceeds the buoyant force in
magnitude.
(c) For a lump of wood of the same
volume, the gravitational force is

7. Statement:
When a body is fully or partially submerged in a
fluid, a buoyant force from the surrounding fluid
acts on the body. The force is directed upward
and has a magnitude equal to the weight mfg of
the fluid that has been displaced by the body.
Archimedes’ Principle
mf is the mass of the fluid that is displaced by the
body.