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प्रश्न
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
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उत्तर
Yes.
संबंधित प्रश्न
Define work.
1 J = ______ calorie.
State the energy transformation on the following:
Electricity is obtained from solar energy.
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.
The work done by a force acting obliquely is given by the formula : W = F cos θ ✕ s. What will happen to the work done if angle θ between the direction of force and motion of the body is increased gradually? Will it increase, decrease or remain constant.
How many watts equal one horse power?
An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate
(i) the amount of work done, (ii) the power of the machine.
If an electric bulb of 100 watt is lighted for 2 hours, how much electric energy would be consumed?
(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?
