Question

The escape velocity on the moon is:
a) 5.64x10^6 m/s
b) 1.68x10^3
c) 160 m/s
d) 2.38x10^3 m/s

Answer 1

potential energy of mass m at surface = -GMmoon m/r

= - m (6.67*10^-11) (7.35*10^22) /(1.74*10^6)
= m (28.2*10^5)

Needs that many Joules of Ke so
(1/2) m v^2 = 2.82*10^6 m

v^2 = 5.64 *10^6
v = 2.37*10^3 = 2370 m/s
by the way:
http://www.1728.org/escvel.htm

Answer 2

thanks! and thanks for the link, its quite useful!