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प्रश्न
Explain by an example that a body may possess energy even when it is not in motion.
उत्तर
A body can have energy even if it is not in motion. The statement can be justified by:
Water stored in the reservoir at the roof of a building possesses gravitational potential energy due to its position above the ground.
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संबंधित प्रश्न
Power spent by a body depends on the time for which it does work.
It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B does the same in 15 s. Compare the Work done.
What is the condition for a force to do work on a body?
What are the units of (a) work, and (b) energy?
What is the work done against gravity when a body is moved horizontally along a frictionless surface?
In case of negative work, the angle between the force and displacement is :
A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s−2, the work by her after climbing 2 m will be :
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What is the work done against gravity when a body is moved horizontally along a frictionless surface?
Complete the following sentences:
1 H.P. = ........ W.
Give an example
Chemical energy changes to electrical energy.
A coolie, with a load of 30 kg on his head, walks on the platform. If he walks a distance of 60 m, what is the work done by him?
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
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]
The weights of two bodies are 2.0 N and 2.0 kgf respectively what is the mass of each body?
