The mass of the earth is 6.0 x 1024kg and that of the moon is 7.0 x 1022kg. If the distance between them is 4.0 x 108m, calculate the force of attraction between them. [G = 6.7 x 10-11Nm2kg-2]

A.

1.8 x 105N

B.

1.8 x 1010N

C.

1.8 x 1015N

D.

1.8 x 1020N

Correct answer is D

F = \(\frac{GM_1M_2}{12^2}\)

F = 6.7 x 10-11x

F = \(\frac{M_1M_2}{R^2}\)

F = \(\frac{6.7 \times 10^{-11} \times 6.0 \times 10^{24} \times 7.0 \times 10^{22}}{(4 \times 10^8)^2}\)

= 1.8 x 1020N