As an object falls from rest, its gravitational potential energy is converted to kinetic energy. Consider a mass m which is falling vertically under the influence of gravity.
Potential Energy = Mass x Gravity x Height
PE = mgh
Kinetic Energy = ½ mv2
KE = ½ mv2
By conservation of energy
Energy before = Energy after
Initial KE + Initial PE = Final KE + Final PE
Object is falling from rest, therefore initial kinetic energy is zero. Once the object hit on the ground, height is zero, therefore no potential energy at ground level.
We can rewrite above equation
Initial PE = Final KE
The mass m on both sides tells us that the final velocity doesn’t depend upon the mass.
Velocity just before the impact is
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