Name: Mechanical Advantage and Efficiency of Machine
Uploaded: 2019-07-19
Duration: 5 min 50 s
Description: Here is a video on the mechanical advantage and efficiency of simple machines and the basic principles behind them. Watch this to know more about this.

Question

What is the law of levers? One end of a uniform weightless rod of length

3 m

is pivoted and works as fulcrum. A load

W

acts on this rod at distance

1 m

from the fulcrum. What minimum effort is required on the other end of the rod to lift this load? What class of lever is this rod? What is its mechanical advantage?

Accepted Answer

An ideal lever works on the principle of moments that states in equilibrium position of the lever.

$E f f o r t \times E f f o r t a r m = L o a d \times L o a d a r m$

$\frac{L o a d}{E f f o r t} = \frac{E f f o r t a r m}{L o a d a r m} . . . (i)$

We know that the mechanical advantage of the lever is defined as the ratio of load to the effort.

$M . A = \frac{L o a d}{E f f o r t} . . . (i i)$

Hence,

$M . A = \frac{E f f o r t a r m}{L o a d a r m}$ , which is law of lever.

To calculate Effort:

Given:

Load, $L = W$

Load arm $= 1 m$

Effort, $E = ?$

Effort arm $= 3 m$

From the principle of the moment,

$L o a d \times L o a d a r m = E f f o r t \times E f f o r t a r m W \times 1 = E \times 3 E = \frac{W}{3}$

It is a class II lever.

To calculate mechanical advantage:

$M . A = \frac{L o a d}{E f f o r t} M . A = \frac{W}{\frac{W}{3}} M . A = 3$

Important Questions on Machines

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