Please explain and use formulasssssss?

Question

1. The radius of Mercury is 2.57 * 10^6m. If g= 3.52N/kg on the surface of Mercury, the mass of Mercury is?

ANS - i dont know pls solvee

2. The Sun has a mass of 1.99 * 10^ 30Kg. Jupiter has a mass of 1.90 * 10^27kg and a mean radius of orbit around the sun of 7.78 * 10^8km. The speed that jupiter travels in its orbit around the sun is?

ANS- 4.70* 10^4 km/h how?

Answer 1

1. M = gr² / G

= (3.52 m/s² x (2.57 x 10^6 m)²) / (6.67 x 10^-11 Nm²/kg²)

= 3.49 x 10^23 kg

2. v = (GM / r)^(1/2)

= (((6.67 x 10^-11 Nm²/kg²) x (1.99 x 10^30 kg)) / (7.78 x 10^11 m))^(1/2)

= 13061.69856 m/s

= 4.70 x 10^4 km/h