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Question
State two reasons, why the efficiency of a pulley system is not 100 percent?
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Solution
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%.
RELATED QUESTIONS
The pulley system has drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.
Fill in the blank:
A pulley is used to change ........................
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The actual maximum load that gets lifted turns out to be 6300 N. What are the values of the actual M.A. and efficiency of the set-up?
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State one advantage of single movable pulley.
