Needs help with pressure and work done

[shogojiawei]

needs help with pressure and work done!

Homework Statement

if a 2 similar rocks are thrown down at different height, one at 100m and 1 at 200m, which one will exert more pressure on the floor?

Homework Equations

The Attempt at a Solution

when i use f=ma, f in both cases are the same as the m and a are the same. since f is the same, pressure should also be the same. however when both rocks hits a can on the ground, the one that is hit by the rock at 200m will get more squash. why? is it because of work done?

 

[The legend]

it's something related to impulse, momentum, collision... if you have learned these chapters it should be easy enough for you to understand.