Question

Prob 1 An astronaut lands on planet Suffrin of known radius R. She throws a rock to a height H directly above her hand (H < R), and she catches it after T seconds. (a) Find the acceleration due to gravity on the surface of Suffrin, in terms of H and T. Ans: (b) Find Suffrin's mass, Ms, in terms of H, T, R and the gravitational constant, G.

Answer 1

a)
let g is the acceleration due to gravity

the time taken to move up T/2 and the time taken to fall back is T/2

while fallling down,

H = voy*t + (1/2)*g*(T/2)^2

H = 0 + (1/8)*g*T^2

g = 8*H/T^2 <<<<<<---------------Answer

b)
we know, g = G*Ms/R^2

so,

G*Ms/R^2 = 8*H/T^2

Ms = 8*H*R^2/(G*T^2) <<<<<---------------Answer