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प्रश्न
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संबंधित प्रश्न
When does a force perform 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.
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 work is done when a body of mass m is raised to a height h above the ground?
State the SI unit of work.
What should be the angle between the direction of force and the direction of motion of a body so that the work done is zero?
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?
Is the motion of moon around the earth in circular path an accelerated motion?
Does the earth move around the sun with a uniform velocity?
Fill in the boxe to show the corresponding energy transformation.
Give an example
Light energy changes to electrical energy.
A body of mass 60 kg has the momentum 3000 kgm/s-1. Calculate: the speed of the body.
(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?
The weights of two bodies are 2.0 N and 2.0 kgf respectively what is the mass of each body?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
