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Unit summary

Revise!

1. What pressure does a computer monitor exert on 7. At what depth in the Caspian Sea does the
a table if the weight of the monitor is 29 N and pressure of water equal 410 kPa?
the surface area of its stand is 300 cm ?
2
textbooks nis edu kz
8. Calculate the pressure lemonade exerts on the
2. What is the weight of a textbook that exerts 200 bottom of a full bottle. Complete all necessary
Pa pressure on a table if the contact area with the measurements on your own. Assume that the
table is 3 dm ? density of lemonade is equal to the density
2
of water.
3. Calculate the area of contact between the
kg
shoulder straps of a backpack and a student’s ρ = 1000 3
shoulders if the weight of the backpack is 30 N m
and it exerts 56 kPa pressure. 9. Estimate the upthrust (Archimedes’) force acting
on you in a pool when you:
4. The gas molecules in a container divided by a
thin flexible wall are shown in the image below. a) dive under the water
The number of molecules on the left is greater b) float on the surface of the water
than the number of molecules on the right. Why
Assume that the density of the body is equal to
does the wall not bend? List and explain the
3
the density of water, ρ = 1000 kg/m .
possible reasons.
10. Find the density of the material of an object
floating on water if 1/3 of its volume is below
the surface.

5. Explain whether the pressure of water on the
bottom of a glass changes if a finger is inserted
into the water without touching either the
bottom or the walls of the glass.
6. Calculate the pressure of water in a river at
a depth of 3 m if the density of the water is
1000 kg/m .
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