Question

State the kind of lever which always has the mechanical advantage less than 1.

• A. LEVER I
• B. LEVER II
• C. LEVER III
• D. Both B and C

Answer 1

The correct option is C

LEVER III

According to the principle of lever,
Load x Load arm = Effort x Effort arm ........(i)

Also, mechanical advantage (MA) of a machine is the ratio of the load overcome to the effort applied, i.e.
MA = $\frac{\text{Load (L)}}{\text{Effort (E)}}$ ......(ii)

From (i) and (ii), we get,
MA = $\frac{\text{Load}}{\text{Effort}}=\frac{\text{Effort arm}}{\text{Load arm}}$

So, mechanical advantage less than 1 means that the effort arm is less than the load arm. This is the case with the class III lever.
In class III levers, the mechanical advantage is less than 1 because effort arm is always smaller than the load arm.