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प्रश्न
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उत्तर
The work done by the gravitational force of the sun on earth during its motion around the sun is zero because at every point, the displacement of earth is perpendicular to the gravitational force of sun i.e.,
W = Fd cos 900 = 0
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संबंधित प्रश्न
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
Derive a relationship between S.I. and C.C.S. unit of work
State two conditions when no work is done by a force.
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
An object is dropped from a height H. when is its
(i) P.E. maximum,
(ii) K.E. maximum,
(iii) P.E. = K.E.?
State the energy changes which take place when A piece of magnesium wire is burnt in a jar of oxygen.
Give an example
Electrical energy changes of sound energy.
A block of mass 30 kg is pulled up a slope, as shown in diagram with a constant speed, by applying a force of 200 N parallel to slope.
A and B are initial and final positions of block.
(i) Calculate the work done by force in moving the block from A to B.
(ii) Calculate P.E. gained by block. [g=10ms-2]
Write the two main conditions are needed for work to be done?
