Answer
a) $F=2.4\times 10^{-12}N$
b) $F=2.4\times 10^{-12}N$
Work Step by Step
(a) According to Newton's universal law of gravitation
$F=G\frac{m_1m_2}{r^2}$
We plug in the known values to obtain:
$F=6.67\times 10^{-11}\times \frac{(0.11)(0.24)}{(0.85)^2}$
$F=2.4\times 10^{-12}N$
(b) As the two forces are equal in magnitude but opposite in direction, the apple also exerts the same force on the orange, that is $F=2.4\times 10^{-12}N$.
