Two objects P and Q of masses 100kg and 20kg respectively are 1.2m apart on a horizontal surface. Calculate the net gravitational force acting on Q.                                     \([G= 6.67 \times 10^{-11} Nm^{2}kg^{-2}]\)

A.

\(1.11\times 10^{-7} N\) towards P

B.

\(1.11\times 10^{-7} N\) towards Q

C.

\(9.26\times 10^{-8} N\) towards P

D.

\(9.26\times 10^{-8} N\) towards Q

Correct answer is D

\(F= \frac{Gm_{1}m_{2}}{r^{2}}\)

\(m_{1} = 100kg\)

\(m_{2} = 20kg; r =1.2m\)

\(G= 6.67\times 10^{-11}\)

\(F = \frac{6.67\times 10^{-11}\times 100\times 20}{(1.2)^{2}} = 9.26\times 10^{-8}\)

The acceleration of each object is inversely proportional to the mass, the lighter object will move a bit faster, hence. the force will act in the direction of Q.