Physics
The mass of the block P is 5 kg. It is to be moved along an inclined plane AC of length 8 m, which makes an angle of 30° with the horizontal. A force of 50 N is applied on the block to move it through the inclined plane AC, as shown in the diagram.
(a) What is the work done by the force along the inclined plane?
(b) Find the gain in potential energy of block P if it is directly lifted to C from the ground. (g = 10 ms-2)
(c) We know that potential energy is gained due to the work done on the body against gravity. Then, in this case, why is the work done on the block and the increase in the potential energy of the block different?
Work, Energy & Power
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Answer
(a) W = F x S = 50 x 8 = 400 J
(b) Given, ∠ A = 30 °, AC = 8 cm
in △ABC,
Potential energy gained = mgh = 5 x 10 x 4 = 200 J
(c) This is because while pushing the block along the inclined plane, some energy is wasted to overcome the friction between the block and the inclined plane.
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