Question

define efficency of lever

Answer 1

Answer:

Lever, simple machine used to amplify physical force. All early people used the lever in some form, for moving heavy stones or as digging sticks for land cultivation. The principle of the lever was used in the swape, or shaduf, a long lever pivoted near one end with a platform or water container hanging from the short arm and counterweights attached to the long arm. A man could lift several times his own weight by pulling down on the long arm. This device is said to have been used in Egypt and India for raising water and lifting soldiers over battlements as early as 1500 BC.

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Answer 2

Answer:

It is usually the ratio of the power delivered by a mechanical system to the power supplied to it, and, because of friction, this efficiency is always less than one. For simple machines, such as the lever and the jackscrew, the efficiency is the actual load lifted divided by the theoretical force delivered.