Law of a Machine and Maximum Mechanical Advantage.

Law of a Machine :

This is define by the relationship between the
Effort applied to a machine to lift the load.To
Iift different loads various effort to be applie
to a machine.If we take the record of various
efforts required to lift the corresponding loads and plot a graph between load lifted and effort applied then generally it will represent a straight line ----which does not pass through the orgin.

In the intercept OA represents the effort required to overcome the frictional resistance as offered by the machine.

Mathematically , the law of a machine can be
Expressed by the relation :

P = mW + C

Where P = Effort applied to raise the load W
m = tan @ = slope of the line AB
= constant which is known as co- efficient of friction .

C = constant ( which represents the machine friction )
= Intercept OA = Effort required to overcome friction.

1. Maximum Mechanical Advantage :

Mechanical Advantage of a machine is given by ;

M.A = W/P = Load lifted / Effort applied

From equation, P = mW + C

= mW = P - C

= W/P = 1/m ( 1- C/P)

= M.A = 1/m (1- C/P)

We see that with the increase of load the effort increases. As the effort increases, C/P value decreases ( Since C is constant).

For small value of C/P,M.A of a machine increase as given by equation. So if P is too large then C/P become negligible and M.A of a machine will be maximum.

Maximum Mechanical Advantage = 1/m.

SK NAJMUL (munna)

Hi. I’m a Mechanical Engineer, are I’m Designer of Blog Magic. I’m Creative Website, Web Designer, Auto Cad 3D and Interaction Designer, Industrial Machine Designer, Web Developer, Business Enthusiast, CNC, Writer and Photo editing and some time research an Mechanical subjects, Inspired to make things looks better.