Okay I'm stuck...Here's the problem I'm dealing with:
An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in 1 second. On this planet, the rock has a weight of:
a) 1 N b) 2 N c) 3 N d) 4 N e) 5 N
first of all which planet...