Question

Why is the actual mechanical advantage of a simple machine different from the ideal mechanical advantage?

Answer 1

In order to solve this question, we should first know about the mechanical advantage of any mechanical machine. So, mechanical advantage is just the advantage which is gained by a machine after performing some work and more simply it’s just the ratio of the force which is used by machine to perform work to the force which was applied on the machine, here we will discuss both actual advantage and ideal mechanical advantage of a machine.

Complete step by step answer:
The actual mechanical advantage denoted by AMA is simply the ratio of output force and input force applied on the machine and its written as
$AMA = \dfrac{{{F_{out}}}}{{{F_{in}}}}$ and this is actual advantage of a machine in the presence of friction caused in performing the mechanical work whereas,
The ideal mechanical advantage uses the principle that the energy which is applied on the body is same amount of energy which a machine uses to perform work, so IMA is calculated in absence of friction and IMA is generally calculated by the ratio of input distance and output distance and written as
$IMA = \dfrac{{{s_{in}}}}{{{s_{out}}}}$
Hence, actual mechanical advantage AMA is different from ideal mechanical advantage IMA because IMA is calculated in absence of friction whereas AMA is calculated in presence of friction.

Note: It should be remembered that, no simple machine is ideal such that a machine never uses whole amount of energy to perform work which was applied on it, a simple machine always lost its energy while performing work in form of heat energy or sound energy so, not any simple machine is an ideal machine.