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प्रश्न
उत्तर
Horse power is the unit of power. The horsepower used for electrical machines is defined as exactly 746 watt.
Classically, a horse exerting 1 H.P. can raise 330 pounds of coal 100 feet in a minutes, or 33 pounds of coal 1,000 feet in one minute, or, 1,000 pounds 33 feet in one minute.
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संबंधित प्रश्न
A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
Name a common device where a gear train is used
Work is said to be done by a forte only when ................
A boy of mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate:
- the force of gravity acting on the boy,
- the work done by him against the force of gravity,
- the power spent by boy. (Take g = 10 m s-2)
Why is the work done on an object moving with uniform circular motion zero?
What is the work done against gravity when a body is moved horizontally along a frictionless surface?
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?
Can work done be zero even if force acts on the body?
List any six forms of energy and write a short note on each of them.
Fill in the boxe to show the corresponding energy transformation.
How is horse power related to the S. I. unit of power?
What should be the characteristic of a source of energy?
(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?
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)
A is a push or a pull ______.
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.
