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प्रश्न
What are the units of (a) work, and (b) energy?
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उत्तर
The units of work and energy are the same.
(a) Work - Joule (J)
(b) Energy - Joule (J)
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संबंधित प्रश्न
In which of the following cases, is work being done?
(i) A man pushing a wall.
(ii) a coolie standing with a load of 12 kgf on his head.
(iii) A boy climbing up a staircase.
How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.
Distinguish between work and power.
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
Give an example
Electrical energy changes to heat energy.
A body of mass 60 kg has the momentum 3000 kgm/s-1. Calculate: the speed of the body.
What is the difference between renewable and non-renewable resources?
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Suma is swimming in a pond.
