Question

Raju weighs $40N$ while Ravi weighs $10N$ lighter than Raju. Four positions $A,B,C,D$ are marked on a see-saw shown in the figure. Identify the probable where Raju must sit so that the seesaw indicated in the figure will be in equilibrium.
(Figure is not to scale)

• A. $A$
• B. $B$
• C. $C$
• D. $D$

Answer 1

The correct option is D $D$

In order to set the see-saw in equilibrium, torque should be balanced.

$\Rightarrow$ Torque produced by Ravi = Torque produced by Raju

But, $\tau =r\times F$

$\Rightarrow$ Ravi's Weight $\times$ Ravi's Distance = Raju's Weight $\times$ Raju's Distance

$\Rightarrow$ 10 $\times$ Ravi's Distance =40 $\times$ Raju's Distance

$\Rightarrow$ Raju must sit at the distance of ${\frac{1}{4}}^{th}$ of Ravi's Distance so that the seesaw indicated in the figure will be in equilibrium.

Therefore, D is the correct option.