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प्रश्न
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person walks on a levelled road.
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उत्तर
Zero work is done.
Explanation:
When a person walks on a levelled, no work is done against the force of gravity, as the displacement of the person is normal to the direction of the force of gravity, which is vertically downwards.
संबंधित प्रश्न
A boy weighing 40 kgf climbs up a stair of 30 steps each 20 cm high in 4 minutes and a girl weighing 30 kgf does the same in 3 minutes. Compare:
- The work done by them.
- The power developed by them.
How is work done by a force measured when the force is in the direction of displacement?
How is the unit horsepower related to the S.I. unit of power?
A body is moved in a direction opposite to the direction of force acting on it. State whether the work is done by the force or work is done against the force
State the condition when the work done by a force is negative. Explain with the help of examples.
How is 1 kgf related to the SI unit of force?
A bullet fired against a window glass pane makes a hole in it without any cracks while a stone striking the same glass pane smashes it; explain with reason.
Calculate the work done when:
A car is moved on a rough road through 30 m against a frictional resistance of 75 N.
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
