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प्रश्न
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
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (see the given figure). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east, as shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.
How is work related to energy?
Give reasons for the following A teacher moving around in the class is doing work but a child standing and reading a book is not doing any work.
.A man raises a box of mass 50kg to a height of 2m in 20s, while another man raises the same box to the same height in 50s. Compare:
(i) the work done, and
(ii) the power developed by them.
Find the kinetic energy of a body of mass 1 kg moving with a uniform velocity of 10 m s-1.
If the work done by a force in moving an object through a distance of 20 cm is 24.2 J, what is the magnitude of the force?
A car is being driven by a force of 2.5 ✕ 1010 N. Travelling at a constant speed of 5 m/s, it takes 2 minutes to reach a certain place. Calculate the work done.
A max X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why?
Each of the following statement describes a force acting. Which force is causing work to be done?
Does the earth move around the sun with a uniform velocity?
A man lifts a mass of 10 kg from the floor to a shelf 4 meter high. If g = 10 ms-2, what is the work done?
Calculate the amount of work done by a child carrying a bag of 20 kg when he moves a distance of 40 m in
(a) Vertical direction, and
(b) Horizontal direction
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]
A water pump raises 50 kg of water through a height of 25 m in 5s. Calculate the power supplied by the pump (Take: g = 10 N kg−1).
What is power? How do you differentiate kilowatt from kilowatt-hour? The Jog Falls in Karnataka state are nearly 20 m high. 2000 tonnes of waterfalls from it in a minute. Calculate the equivalent power if all this energy can be utilized? (g = 10 m s–2)
