Question

A planet has mass 6.4×10*24kg and radius 3.4×10*6m.Calculate energy required to remove an object of mass 800kg from the surface of the planet to infinity.​

Answer 1

Answer:

126.1 MJ/kg

Explanation:

Mass of planet = 6.4×10^24 kg

Radius = 3.4×10^6 m

G = 6.7*10^(-11) Nm^2/kg^2

The gravitational potential at surface is:

P = -(G*M)/r

= - [6.7*10^(-11) × 6.4×10^24 ]/3.4×10^6

= - 12.61 × 10^7

= -1.261 × 10^8 J/kg

P= -126.1 MJ/kg

Now if 10MJ/kg work is done to lift a particle to some height from surface the potential will be -116.1 MJ/kg .

So, the required work = 126.1 MJ/kg

[raised to a height where gravitational potential reaches zero . From 0 to infinity it can not be measured ]

Answer 2

Answer:

shouldnt we multiply mass of spacecraft to potential

Explanation:

as potential is work done per unit mass