Question

An almond nut can be cracked open by a lever of length 1m by applying a force of 100N. If the force is to be reduced to 25 N, what should be the length of the effort arm?

• A. 20 m
• B. 3 m
• C. 4 m
• D. 2 m

Answer 1

The correct option is C

4 m

Given: When effort = 100 N, effort arm = 1m.
We need to find the effort arm when the effort is 25 N.
Let the required effort arm be x.

We know that
$\text{effort}\times \text{effort arm}=\text{Load}\times \text{Load arm}$

Hence, $100\times 1=\text{Load}\times \text{Load arm}$ ...... (1)
And, $25\times x=\text{Load}\times \text{Load arm}$ ........ (2)

Since the same almond nut is to be cracked, the product $\text{Load}\times \text{Load arm}$ remains constant.
Thus, from 1 and 2, we get

$100\times 1m=25\times x$

$\Rightarrow x=\frac{100}{25}$

x = 4

Length of the lever is 4 m.