Question

A fulcrum divides a crowbar in the ratio $3:1$. What weight will be lifted if an effort of $100\mathrm{N}$ is applied at the end of its long arm?

• A. $400\mathrm{N}$
• B. $100\mathrm{N}$
• C. $300\mathrm{N}$
• D. $500\mathrm{N}$

Answer 1

The correct option is C

$300\mathrm{N}$

Step 1: Given data,

Ratio of effort arm and load arm is $3:1$

Effort in the given case is $100\mathrm{N}$

Step 2: Find the load,

As we know that $\frac{\mathrm{load}}{\mathrm{effort}}=\frac{\mathrm{effort}\mathrm{arm}}{\mathrm{load}\mathrm{arm}}$

Substitute the given values,

$\begin{array}{rcl}\frac{\mathrm{load}}{100\mathrm{N}}& =& \frac{3}{1}\\ \mathrm{load}& =& 100\times 3\\ \mathrm{load}& =& 300\mathrm{N}\end{array}$

Therefore, the load is $300\mathrm{N}$.

Hence, the correct option is (C).