Advertisements
Advertisements
प्रश्न
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Food grains are getting dried in the sun.
Advertisements
उत्तर
The grains of corn are drying in the heat of the sun; here, also, no work is being done because the grains are stable in their place. There is no displacement in them.
APPEARS IN
संबंधित प्रश्न
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.
A machine raises a load of 750 N through a height of 16 m in 5 s. calculate:
- energy spent by machine,
- power at which the machine works.
State the SI unit of work.
Is it possible that a force is acting on a body but still the work done is zero? Explain giving one example.
The work done on an object does not depend on the :
(a) Define power and name its unit.
(b) A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.
How fast should a boy weighting 30 kg run so that his kinetic energy is 375 joule?
What are the advantages and disadvantages of using solar cells for producing electricity?
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 |
