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संबंधित प्रश्न
No work is done by a force if the body
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.
How much energy is gained by a box of mass 20 kg when a man, carrying the box waits for 5 minutes for a bus?
Define 1 joule of work.
When is the work done by a force on a body : (a) positive, (b) negative, and (c) zero?
When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.
Choose one or more correct alternatives.
For work to be performed, energy must be ______.
- transferred from one place to another
- concentrated
- transformed from one type to another
- destroyed
Write an expression for the work done against gravity.
Complete the following sentences:
Joule is the unit of .......
A body does 20 J of work in 10 s. What is its power?
List any six forms of energy and write a short note on each of them.
Name two places in India where electricity is generated from nuclear power plants.
How long should an electric motor, of power 2 H.P. operate, so as to pump 5 m3 of water from a depth of 15m. [Take g = 10 N kg−1]
If a ball is dropped on the sloping roof of a house, it acquires ______ and falls on the ground. That is the transformation of ______ energy into ______ energy takes place.
(kinetic, potential, motion)
Who is the odd one out?
A force can cause an object to change its ______.
What is work?
