Question

The earth (mass $=6 \times 10^{24} \,kg$ ) revolves around the sun with an angular velocity of $2 \times 10^{-7}\, rad / s$ in a circular orbit of radius $1.5 \times 10^{8} \,km$. The force exerted by the sun on the earth, in newton, is

• A. $ 36 \times {10}^{21}$
• B. $ 27 \times {10}^{39}$
• C. zero
• D. $ 18 \times {10}^{25}$

Answer 1

Answer: (A)

Mass $(m)=6 \times 10^{24} kg$;
Angular velocity $(\omega)=2 \times 10^{-7} rad / s$ and
radius $(r)=1.5 \times 10^{8} km =1.5 \times 10^{11} m$.
Force exerted on the earth $=m R \omega^{2}$
$=\left(6 \times 10^{24}\right) \times\left(1.5 \times 10^{11}\right) \times\left(2 \times 10^{-7}\right)^{2}$
$=36 \times 10^{21} N$