Advertisements
Advertisements
Question
When a body moves in a circular path, how much work is done by the body? Give reason.
(Hint: The body is acted upon by the centripetal force.)
Solution
When a body moves in a circular path, no work is done since the force on the body is directed towards the centre of circular path (the body is acted upon by the centripetal force), while the displacement at all instants is along the tangent to the circular path, i.e., normal to the direction of force.
APPEARS IN
RELATED QUESTIONS
When a body is placed on a table top, it exerts a force equal to its weight downwards on the table top but does not move or fall
1) Name the force exerted by the table top
2) What is the direction of the force?
A coolie X Carrying a load on his head climbs up a slope and another coolie Y carrying the identical load on his head move the same distance on a frictionless horizontal platform. Who does more work? Explain the reason.
How is kilowatt hour related to joule?
What is meant by a rotatory motion? Give one example.
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
Justify the statement. “Power can be expressed as the product of force and velocity.”
A coolie carrying a load on his head and moving on a frictionless horizontal platform does no work. Explain the reason why.
State the C.G.S. unit of work. How it is related to its S.I. unit?
For the following scenarios, state whether the work done by gravity is positive, negative, or zero.
A person climbs a ladder.
