Question

A girl of weight $W$ is sitting on an electric swing rotating in a vertical plane. She feels her weight to have increased by $25\%$ as the swing goes up. What weight she would experience when the swing comes down?

• A. $\frac{3W}{2}$
• B. $\frac{5W}{4}$
• C. $\frac{3W}{4}$
• D. $\frac{W}{2}$

Answer 1

Answer: (C)

$\frac{3W}{4}$

A girl of weight $W$ is setting on an electric swing rotating in a vertical plane, She feels the weight increased by 25%

When a girl goes up.

$W^{\prime }=W+F$

$F=W^{\prime }-W$

$F=1.25W-W=0.25W$

When girls come down, weight experienced is given by :

$W^{\prime }=W-F$

$W=W-0.25W=0.75W$

$W^{\prime }=\frac{3}{4}W$

The correct option is C.