Question

If the mass of one particle is increased by 50 % and the mass of another particle is decreased by 50 %, the gravitational force between them

• A. decreases by 25%
• B. decreases by 75 %
• C. increases by 25%
• D. does not change

Answer 1

Answer: (A)

decreases by 25%

$Massofparticle1=m_{1}Massofparticle2=m_{2}Distancebetweenparticles=dInitialforce=G\frac{m_1{m}_2}{d^2}Finalforce=G\frac{(m_1+\frac{m_1}{2})(m_2-\frac{m_2}{2})}{d^2}=G\frac{m_1{m}_2}{d^2}\times \frac{3}{4}\Rightarrow Finalforce=\frac{3}{4}\times Initialforce$