1. Rubber sucker– this is a shallow rubber cap. Before use it is moistened to get a good
seal then pressed firmly on a smooth surface so that the air inside is pushed out. The
atmospheric pressure will then hold it firmly
against the surface as shown below. They are used by
printing machines to lift papers, lifting glass panes,
2. Drinking straw– when a liquid is drawn using a straw air is sucked through the straw
to the lungs. This leaves the space in the straw partially evacuated. The atmospheric
pressure pushing down the liquid in the container becomes greater than the
pressure inside the straw and this forces the liquid into your mouth.
3. The syringe– they work in the principle as the straw. They are used by the doctors in
hospitals for giving injections.
4. Bicycle pump– it uses two valves, one in the pump (greasy leather) and the other in
the tire. When the handle is pushed in, the pressure inside the barrel becomes
greater than the one in the tire and this pushes air inside. The valve in the tire is
made such that air is locked inside once pumped.avy metal sheets
5. The siphon– it is used to empty tanks which may not be easy to empty by pouring
their contents out. The tubing must be lowered below the base of the tank. The
liquid flows out due to pressure difference caused by the difference in height (h ? g).
Moraa orina answered the question on April 4, 2018 at 18:03
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The height of the mercury column in a barometer is found to be 67.0 cm at a certain place.
What would be the height of...
(Solved)
The height of the mercury column in a barometer is found to be 67.0 cm at a certain place.
What would be the height of a water barometer at the same place? (densities of mercury-
1.36 × 104
kg/m3
and water- 1.0 × 103
kg/m3
).
Date posted:
April 4, 2018
.
Answers (1)
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The density of mercury is 13,600 kgm-3
. Determine the liquid pressure at a point 76 cm
below the surface of mercury. (Take g = 10...
(Solved)
The density of mercury is 13,600 kgm-3
. Determine the liquid pressure at a point 76 cm
below the surface of mercury. (Take g = 10 Nkg-1
)
S
Date posted:
April 4, 2018
.
Answers (1)
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A diver is 10 m below the surface of water in a dam. If the density of water is 1,000 kgm-3
, determine the pressure due...
(Solved)
A diver is 10 m below the surface of water in a dam. If the density of water is 1,000 kgm-3
, determine the pressure due to the water on the diver. (Take g = 10 Nkg-1
)
Date posted:
April 4, 2018
.
Answers (1)
-
An astronaut weighs 900 N on earth. On the moon he weighs 150 N. Calculate the moons’
gravitational strength. (Take g = 10 N/kg)
(Solved)
An astronaut weighs 900 N on earth. On the moon he weighs 150 N. Calculate the moons’
gravitational strength. (Take g = 10 N/kg)
Date posted:
April 3, 2018
.
Answers (1)
-
100 cm3
of fresh water of density 1,000 kgm-3
is mixed with 100 cm3
of sea water of density
1030 kgm-3
. Calculate the density of the mixture
(Solved)
100 cm3
of fresh water of density 1,000 kgm-3
is mixed with 100 cm3
of sea water of density
1030 kgm-3
. Calculate the density of the mixture
Date posted:
April 3, 2018
.
Answers (1)
-
The relative density of some type of wood is 0.8. Find the density of the wood in kg/m3
(Solved)
The relative density of some type of wood is 0.8. Find the density of the wood in kg/m3
Date posted:
April 3, 2018
.
Answers (1)
-
The density of concentrated sulphuric acid is 1.8 g/cm3
. Calculate the volume of 3.1
kg of the acid.
(Solved)
The density of concentrated sulphuric acid is 1.8 g/cm3
. Calculate the volume of 3.1
kg of the acid.
Date posted:
April 3, 2018
.
Answers (1)
-
A block of glass of mass 187.5 g is 5.0 cm long, 2.0 cm thick and 7.5 cm high.
Calculate the density of the glass...
(Solved)
A block of glass of mass 187.5 g is 5.0 cm long, 2.0 cm thick and 7.5 cm high.
Calculate the density of the glass in kgm-3
.
Date posted:
April 3, 2018
.
Answers (1)
-
Example
100 cm3
of fresh water of density 1,000 kgm-3
is mixed with 100 cm3
of sea water of density
1030 kgm-3
. Calculate the density of the mixture.
(Solved)
Example
100 cm3
of fresh water of density 1,000 kgm-3
is mixed with 100 cm3
of sea water of density
1030 kgm-3
. Calculate the density of the mixture.
Date posted:
April 3, 2018
.
Answers (1)
-
A polar bear appears to be upside down in the sky. Explain
(Solved)
A polar bear appears to be upside down in the sky. Explain
Date posted:
March 26, 2018
.
Answers (1)
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A machine has an efficiency of 80%.if the machine is required to overcome a load of 60N with a force of 40N. Calculate the velocity ratio?
(Solved)
A machine has an efficiency of 80%.if the machine is required to overcome a load of 60N with a force of 40N. Calculate the velocity ratio?
Date posted:
March 22, 2018
.
Answers (1)
-
State TWO reasons why the earth pin in a three pin plug is longer than the others
(Solved)
State TWO reasons why the earth pin in a three pin plug is longer than the others
Date posted:
March 14, 2018
.
Answers (1)
-
Describe on how to measure the volume of oil drop
(Solved)
Describe on how to measure the volume of oil drop.
Date posted:
March 6, 2018
.
Answers (1)
-
Describe an experiment on how to measure the thickness of a razor Blade
(Solved)
Describe an experiment on how to measure the thickness of a razor Blade
Date posted:
March 6, 2018
.
Answers (1)
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A butcher has a beam balance and masses 0.5kg and 2kg. How would he measure 1.5kg of meat on the balance at once
(Solved)
A butcher has a beam balance and masses 0.5kg and 2kg. How would he measure 1.5kg of meat on the balance at once.
Date posted:
March 5, 2018
.
Answers (1)
-
State two measurements you would take in an experiment to determine the upthrust of the object
(Solved)
State two measurements you would take in an experiment to determine the upthrust of the object.
Date posted:
March 3, 2018
.
Answers (1)
-
The density of granite is 2800kg/m3.What is the specific gravity of granite?.
(Solved)
The density of granite is 2800kg/m3.What is the specific gravity of granite?.
Date posted:
February 26, 2018
.
Answers (1)
-
A butcher has a beam balance and masses 0.5kg and 2.0kg. How would he measure 1.5kg of meat on the balance at once?
(Solved)
A butcher has a beam balance and masses 0.5kg and 2.0kg. How would he measure 1.5kg of meat on the balance at once?
Date posted:
February 26, 2018
.
Answers (1)
-
Explain how an electric bell works.
(Solved)
Explain how an electric bell works.
Date posted:
February 20, 2018
.
Answers (1)
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A screw jack 25% efficient and having a screw pitch of 0.4cm is used to raise a load through a certain height. If the process...
(Solved)
A screw jack 25% efficient and having a screw pitch of 0.4cm is used to raise a load through a certain height. If the process the handle turns through a circle of radius 40cm. Calculate the
1. Velocity ratio of the machine
2. Mechanical advantage of the machine
3. Effort required to raise a load of 1000N with the machine ( take pi =3 1/4)
Date posted:
February 12, 2018
.
Answers (1)