Question

Mechanical advantage (M.A.), load (L), and effort (E) are related as:
A) $M.A = L \times E$
B) $L = E \times M.A$
C) $E = M.A \times L$
D) $None$

Answer 1

Hint: First let us see in brief what these terms mean. Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device, or machine system. The machine preserves the input power and simply trades off input forces against movement to obtain a desired amplification in the output force. The model for this is the law of the lever. Now load can be understood as the external mechanical resistance against which a machine (such as a motor or engine), acts. And the effort can be thought of as the force applied to the machine to make the machine able to work. For example, if you are riding a bicycle. Here the bicycle is a machine and the force applied to the paddles is the effort. Now it makes sense that all three are interrelated.

Complete answer:
Step 1: Define the mechanical advantage in terms of load and effort. The ratio of load lifted by a machine to the effort applied on a machine is called the mechanical advantage of the machine. If we take the example of the bicycle again then the mechanical advantage of the bicycle will be the ratio of the work which is done by bicycle to the effort which is applied by the bicycle rider to the bicycle.
Step 2: If we denote the mechanical advantage by $M.A$ , the load by $L$ , and the effort by $E$ then we can write that
$\therefore M.A = \dfrac{L}{E}$
$ \Rightarrow L = M.A \times E$

Therefore the correct option is B.

Note: Greater the value of the mechanical advantage of a machine, the easier is the work done. This is because if the value of the mechanical advantage is greater this means that the value of effort is less. Therefore the work can be done easily. When machines are designed the mechanical advantage is always tried to keep greater. But the value of mechanical advantage cannot be greater than 1. Because the value of load cannot be greater than effort.