Question

If mass of planet is 8 times that of earth and its radius is twice the radius of the earth, what will be the escape velocity of planet ?(esc velocity of earth -11.2km/s)

Answer 1

Given data

Mass of Planet is 8 times of earth

Radius of Planet is twice than earth.

If Earth's Mass = M

Earth's radius = R

Solution

As we know that the equation for escape velocity  

v = √(2 g r)

 If Planet's mass is eight times greater then escape velocity = 2 √2 times.  

Escape velocity is lowered by 1/√2. If radius increased by two times. Then net escape velocity will be increase.  

2 √2 ×  (1/√2)= 2 times  

It is shown that the escape velocity of planet will be 2 times than earth.

Escape velocity of the earth = 11.2 km/s

Escape velocity of that planet = 2 × 11.2 = 22.4 km/sec.

Planet's escape velocity will be 22.4 km/s.