Posted by Andy on .
If an astronaut dropped a small rock near the surface of Pluto, how far (in m) would the rock fall in 1.1 s? (The mass of Pluto is 2.500×103 the mass of earth and the radius of Pluto is 0.18 of the earth's radius.)

physics 
drwls,
g of a spherical body is proportional to M/R^2.
Therefore, g on the surface of Pluto will be lower than that of Earth, by a factor
2.5*10^3*/0.18^2 = 0.077
That means the value of g for Pluto (which I will call g') is 0.75 m/s^2
Use the standard formula for the distance fallen:
X = (1/2)g' t^2, where t = 1.1 s.