To lubricate the engine/ reduce frictional force.
Wilfykil answered the question on March 22, 2019 at 10:00
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In the study of a free fall, it is assumed that the force f acting on a given body of mass m is gravitational, given...
(Solved)
In the study of a free fall, it is assumed that the force f acting on a given body of mass m is gravitational, given by F= mg. State two other forces that act on the same body.
Date posted:
March 22, 2019
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Answers (1)
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A student was heard saying “the mass of a ball on the moon is one sixth its mass on earth”. Give a reason why this...
(Solved)
A student was heard saying “the mass of a ball on the moon is one sixth its mass on earth”. Give a reason why this statement is wrong.
Date posted:
March 22, 2019
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Answers (1)
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Explain how to calculate the efficiency of the pulley system when the weight of load and effort is given
(Solved)
Explain how to calculate the efficiency of the pulley system when the weight of load and effort is given.
Date posted:
March 19, 2019
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Answers (1)
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A vacuum pump was used to pump out air from the glass tube immersed in liquids as shown in the figure below . After sometimes...
(Solved)
A vacuum pump was used to pump out air from the glass tube immersed in liquids as shown in figure below.
After sometimes the level of paraffin rose to position X.mark Y,the corresponding positions for the water level .Give a reason for your answer.
Date posted:
March 18, 2019
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Answers (1)
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A metre rule is pivoted at the 20cm mark and it hangs at the 90cm mark from a spring balance 75g wt. Where is the...
(Solved)
A metre rule is pivoted at the 20cm mark and it hangs at the 90cm mark from a spring balance 75g wt. Where is the centre of gravity of the metre rule if it weighs 125g?
Date posted:
March 2, 2019
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Answers (1)
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Suggest why the rate of heat flow through a pane of glass is greater on a windy day
(Solved)
Suggest why the rate of heat flow through a pane of glass is greater on a windy day.
Date posted:
February 26, 2019
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Answers (1)
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An electric kettle with a shiny outer surface would be more efficient than one with a dull outer surface. Explain
(Solved)
An electric kettle with a shiny outer surface would be more efficient than one with a dull outer surface. Explain
Date posted:
February 23, 2019
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Answers (1)
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How many images would be seen from two mirrors when reflecting surfaces make an angle of 60 degree with each other?
(Solved)
How many images would be seen from two mirrors when reflecting surfaces make an angle of 60 degree with each other?
Date posted:
February 23, 2019
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Answers (1)
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A body weighs 32N in kerosene and 30N in water. If the body weighs 40N in air, find the relative density of kerosene.
(Solved)
A body weighs 32N in kerosene and 30N in water. If the body weighs 40N in air, find the relative density of kerosene.
Date posted:
February 11, 2019
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Answers (1)
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A metal block of density 7.8g/cm3 weighs 117N in air. Find the weight of the block when fully immersed in water of density 1.0g/cm3.
(Solved)
A metal block of density 7.8g/cm3 weighs 117N in air. Find the weight of the block when fully immersed in water of density 1.0g/cm3.
Date posted:
February 2, 2019
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Answers (1)
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A particle revolves at 2Hz in a circle of radius 2m. Calculate its linear speed and angular velocity.
(Solved)
A particle revolves at 2Hz in a circle of radius 2m. Calculate its:
a) Linear speed
b) Angular velocity
Date posted:
January 29, 2019
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Answers (1)
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A screen is placed 80cm from an object. A lens is used to produce on the screen an image with a magnification of 3. What...
(Solved)
A screen is placed 80cm from an object. A lens is used to produce on the screen an image with a magnification of 3. What is the distance between the object and the lens? Calculate the focal length of that lens.
Date posted:
January 21, 2019
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Answers (1)
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A bullet is shot vertically upward and rises for a maximum height of 1000 m. What is the initial velocity...
(Solved)
A bullet is shot vertically upward and rises for a maximum height of 1000m. What is the initial velocity of the bullet and the total time of flight?
Date posted:
January 14, 2019
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Answers (1)
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Explain why during anomalous expansion of water, heat transfer is limited to conduction and radiation
(Solved)
Explain why during anomalous expansion of water, heat transfer is limited to conduction and radiation.
Date posted:
December 30, 2018
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Answers (1)
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State a reason why it may not be possible to suck a liquid into your mouth using drinking straw on the surface of the moon
(Solved)
State a reason why it may not be possible to suck a liquid into your mouth using drinking straw on the surface of the moon.
Date posted:
December 10, 2018
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Answers (1)
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State the reason why the speed of the water at the narrow section of a river is higher than at the wider section
(Solved)
State the reason why the speed of the water at the narrow section of a river is higher than at the wider section.
Date posted:
November 29, 2018
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Answers (1)
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A radioactive element has an initial count rate of 2,400 counts per minute on a scaler. The count rate falls to 300 units per minute...
(Solved)
A radioactive element has an initial count rate of 2,400 counts per minute on a scaler. The count rate falls to 300 units per minute in 30 hours, (a) Calculate the half-life of the element (b) If the initial number of atoms in another sample of the same element is 6.0 × 1020, how many atoms will have decayed in 50 hours?
Date posted:
October 17, 2018
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Answers (1)
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The initial number of atoms in a sample is 5.12 × 1020. If the half-life of the sample is 3.0 seconds, determine the number of...
(Solved)
The initial number of atoms in a sample is 5.12 × 1020. If the half-life of the sample is 3.0 seconds, determine the number of atoms that will have decayed after six seconds.
Date posted:
October 17, 2018
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Answers (1)
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The half-life of a sample of a radioactive substance is 98 minutes. How long does it take for the activity of the sample to reduce...
(Solved)
The half-life of a sample of a radioactive substance is 98 minutes. How long does it take for the activity of the sample to reduce to 1/16th of the original value?
Date posted:
October 17, 2018
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Answers (1)
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Explain ways of detecting nuclear radiation
(Solved)
Explain ways of detecting nuclear radiation.
Date posted:
October 17, 2018
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Answers (1)