Question

The earth (mass = $6\times 10^{24} \, kg$ ) revolves around the sun with angular velocity $2\times 10^{- 7} \, rad \, s^{- 1}$ in a circular orbit of radius $1.5\times 10^{11} \, m$ . 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 the required centripetal force.
$F=mR\omega ^{2}$
$=6\times \left(10\right)^{24}\times \left(1.5 \times \left(10\right)^{11}\right)\left(2 \times \left(10\right)^{- 7}\right)^{2}$
$=36\times 10^{21 \, }N$