Question

The earth (mass = $6\times 10^{24}$ kg) revolves around the sun with angular velocity $2\times 10^{- 7} \, rads^{- 1}$ in a circular orbit of radius $1.5\times 10^{11}$ km. The force exerted by the sun on the earth in newton is

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

Answer 1

Answer: (D)

Gravitational force exerted by the sun on the earth will provide required centripetal force
$F=mR \, \omega ^{2}$
$=6\times \left(10\right)^{24}\times \left(1.5 \times \left(10\right)^{11}\right)\left(2 \times \left(10\right)^{- 7}\right)^{2}$
$=36\times 10^{21}N$