# Does an object stop dead after it is dropped and hits the floor?

1. Jun 2, 2012

### goomer

Say you have a capped water bottle and you drop it so the cap hits the ground and then the bottle falls over. Would the force with which the bottle FALLS OVER (not when the cap hits the ground) and hits the ground be the same as if you balanced the bottle on its cap on the floor and then pushed it so it falls and hits the floor?

2. Jun 3, 2012

### tiny-tim

hi goomer!
things don't fall with force, they fall with speed (or angular speed)

if the bottle lands perfectly balanced, and then falls over simply because it's unstable (ie for the same reason it would fall over if you carefully placed it there), then the initial angular speed would be zero, and yes the final angular speed would be the same

if the bottle lands unbalanced, then, by conservation of angular momentum, the initial angular speed would be non-zero, and the final angular speed would be greater

(though if the bottle was half-full of water, i suspect that some of the water would bounce up immediately on landing, giving a slightly greater moment of inertia that would decrease as the water returned towards the cap, thus slightly increasing the angular speed)