Question

Two bodies of equal masses are some distance apart. If $20\%$ of mass is transferred from the first body to the second body, then the gravitational force between them

• A. incroases by $4\%$
• B. incroases by $14\%$
• C. decreases by $4\%$
• D. decreases by $14\%$

Answer 1

Answer: (C)

Initially force,
$F_1=\frac{G{m}^2}{r^2}$
When $20\%$ mass is transferred from one body to another, then their masses are
$m_1=\frac{80}{100}m$ and $m_2=\frac{120}{100}m$
So, force is finally
$F_2=\frac{G{m}^2}{r^2}\times \left(\frac{24}{25}\right)$
Hence, reduction in $F_2$ is $\frac{F_1-F_2}{F_1}\times 100\%=-4\%$