Question

The weight of a body on surface of earth is $12.6N$. When it is raised to a height half the radius of earth its weight will be

• A. $2.8N$
• B. $5.6N$
• C. $12.5N$
• D. $25.2N$

Answer 1

The correct option is B $5.6N$

Given : $W_o=12.6N$ $h=R/2$

Weight of body at a height h, $W^{\prime }=W_o(\frac{R}{R+h}{)}^2$

$\therefore$ $W^{\prime }=12.6(\frac{R}{R+R/2}{)}^2$

Or $W^{\prime }=12.6\times \frac{4}{9}=5.6N$