Calculate the acceleration due to gravity on the surface of a satellite having a mass of 7 . 4 × 10 22 kg and a radius of 1 . 74 × 10 6 m ( G = 6 . 7 × 10 - 11 N m 2 kg 2 ) . Which satellite do you think it would be?

Given mass of satellite M = 7 . 4 × 10 22 kg , R = 1 . 74 × 10 6 m , G = 6 . 7 × 10 - 11 N m 2 kg 2 we know that acceleration due to gravity on a planet is g = G M R 2 → ( 1 ) Substituting the above values we get g = 6 . 7 × 10 - 11 × 7 . 4 × 10 22 1 . 74 × 10 6 × 1 . 74 × 10 6 ⇒ g = 16 . 376 10 ⇒ g = 1 . 63 m s 2 . 1 . 63 is approximately 1 6 t h of 9 . 8 , and we know that g on earth is approximately 6 times of g on moon. So the satellite would be moon.

The mass of a planet is 6 × 10 24 kg and its diameter is 12 . 8 × 10 3 km . If the value of gravitational constant be 6 . 7 × 10 - 11 N m 2 kg 2 , calculate the acceleration due to gravity on the surface of the planet. What planet could this be?

Given, mass of planet M = 6 × 10 24 kg diameter of planet d = 12 . 8 × 10 3 km ⇒ R = 6 . 4 × 10 6 m ( 1 km = 10 3 m ) . G = 6 . 7 × 10 - 11 N m 2 kg 2 We know g on surface of the planet is given by the equation g = G M R 2 → ( 1 ) Substituting the given values in equation, we get g = 6 . 7 × 10 - 11 × 6 × 10 24 6 . 4 × 10 6 × 6 . 4 × 10 6 ⇒ g = 9 . 8 m s 2 Since the value of g on earth is 9 . 8 m s 2 , the given planet could be earth.