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प्रश्न
Is work done a scalar or a vector physical quantity?
उत्तर
Work is a scalar quantity because it is a measure of transfer of energy without indicating any direction.
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संबंधित प्रश्न
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A sailboat is moving due to wind energy.
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east, as shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.
The moon is revolving around the earth in a circular path. How much work is done by the moon?
Give reasons for the following. No work is done if a man is pushing against a wall.
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
State two disadvantages of producing hydroelectricity.
How much work is done when a force of 1 N moves a body through a distance of 1 m in its own direction?
A force of 50 N acts on a body and moves it a distance of 4 m on horizontal surface. Calculate the work done if the direction of force is at an angle of 60° to the horizontal surface.
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
When you move upstairs, do you perform some work?
Give two examples of work done.
Write an expression for work done by a force depends?
Can work done be zero even if force acts on the body?
Give an example
Electrical energy changes to heat energy.
Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
