Air molecules near the earth’s surface are denser than the air molecules further above the earth. When heating by sun heat, they became lighter and move upward not downward.
chrispohmomanyi answered the question on September 20, 2017 at 07:20
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The activity of a radioactive substance, initially at 400 counts per second reduces to 50 counts per
second in 72 minutes. Determine the half – life...
(Solved)
The activity of a radioactive substance, initially at 400 counts per second reduces to 50 counts per
second in 72 minutes. Determine the half – life of the substance
Date posted:
September 19, 2017
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Answers (1)
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Distinguish between semiconductor and conductors
(Solved)
Distinguish between semiconductor and conductors
Date posted:
September 19, 2017
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Answers (1)
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Which instrument which can be used to measure the thickness of the hair
(Solved)
Which instrument which can be used to measure the thickness of the hair.
Date posted:
September 19, 2017
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Answers (1)
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State the accuracy of a vernier caliper.
(Solved)
State the accuracy of a vernier caliper.
Date posted:
September 19, 2017
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Answers (1)
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State the difference between conductors and insulators
(Solved)
State the difference between conductors and insulators
Date posted:
September 19, 2017
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Answers (1)
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Explain why boiling water is not used to sterilize clinical thermometer.
(Solved)
Explain why boiling water is not used to sterilize clinical thermometer.
Date posted:
September 19, 2017
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Answers (1)
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State any two reasons why water is not a suitable thermometric fluid.
(Solved)
State any two reasons why water is not a suitable thermometric fluid.
Date posted:
September 19, 2017
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Answers (1)
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State why concrete is usually reinforced with steel in the construction of beams
(Solved)
State why concrete is usually reinforced with steel in the construction of beams.
Date posted:
September 19, 2017
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Answers (1)
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Explain why trees bends towards a busy highway.
(Solved)
Explain why trees bends towards a busy highway.
Date posted:
September 19, 2017
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Answers (1)
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Differentiate between pressure and force
(Solved)
Differentiate between pressure and force
Date posted:
September 19, 2017
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Answers (1)
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State any two special rays used in the construction of ray diagrams
(Solved)
State any two special rays used in the construction of ray diagrams
Date posted:
September 19, 2017
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Answers (1)
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A car can be brought to rest from a speed of 20 ms-1 in a time of 2s.
(i) Calculate the average deceleration
(ii) If the driver’s...
(Solved)
A car can be brought to rest from a speed of 20 ms-1 in a time of 2s.
(i) Calculate the average deceleration
(ii) If the driver’s reaction time is 0.2s, determine the shortest stopping distance
Date posted:
September 19, 2017
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Answers (1)
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State how eddy currents are reduced in a transformer
(Solved)
How are eddy currents in the transformer minimized?
Date posted:
September 19, 2017
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Answers (1)
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State three factors that affect the speed of sound in the air
(Solved)
State three factors that affect the speed of sound in the air
Date posted:
September 19, 2017
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Answers (1)
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Define the term wave
(Solved)
Define the term wave
Date posted:
September 19, 2017
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Answers (1)
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The number of molecules in 18cm^3 of a liquid is 6 x 10^23. Assuming that the diameter of the
molecules is equivalent to the side of...
(Solved)
The number of molecules in 18cm^3 of a liquid is 6 x 10^23. Assuming that the diameter of the
molecules is equivalent to the side of a cube having the same volume as the molecule. Determine
the diameter of the molecule.
Date posted:
September 19, 2017
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Answers (1)
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State factors affecting the spring constant of the spring
(Solved)
State factors affecting the spring constant of the spring
Date posted:
September 19, 2017
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Answers (1)
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State factors that determine the force on a current carrying conductor on the magnetic field
(Solved)
State factors that determine the force on a current carrying conductor on the magnetic field
Date posted:
September 19, 2017
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Answers (1)
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State any three characteristics of images formed by a convex mirror
(Solved)
State any three characteristics of images formed by a convex mirror
Date posted:
September 19, 2017
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Answers (1)
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State two types of curved mirrors
(Solved)
State two types of curved mirrors
Date posted:
September 19, 2017
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Answers (1)