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प्रश्न
State two reasons, why the efficiency of a pulley system is not 100 percent?
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उत्तर
The two reasons are:
(i) Some effort is used (or wasted) in overcoming the friction between the string and the grooves of the pulleys.
(ii) Some effort is used up (wasted) in lifting up the movable block along with the load.
On account of the above two reasons, effort applied is always more than the load lifted up and so the M.A. is always less than 1. Hence efficiency is always less than 100%.
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संबंधित प्रश्न
From the diagram given below. answer the question that follows:

1) What kind of pulleys are A and B?
2) State the purpose of pulley B.
3) What effort has to be applied at C just raise the load L = 20 kgf?
(Neglect the weight of pulley A and friction)
The pulley system has drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.
Is the above pulley system an ideal machine or not?
State two functions of a machine.
In a gear system, the gear ration of the driving wheel A and driven wheel B is 10:1. To rotate the driven wheel B in the direction of driving wheel A, the driving wheel A is engaged with other wheel C. what should be the gear ratio of the wheels A and C?
Give reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
Give reason for the following:
In case of a block and tackle arrangement, the mechanical advantage increases with the increase in the number of pulleys.
Name the type of single pulley that can act as a force multiplier. Draw a labeled diagram of the pulley mentioned by you.
What is the relation between the mechanical advantage and the number of strands of string used to support the load, in a ‘block and tackle’ set-up?
What is a pulley?
