How do you work out the speed of an object?

If you need to include the effects of air resistance, then the answer is more complicated

than you want to deal with.

If you're satisfied to ignore air resistance, then the weight doesn't make any difference. We've known

for the past 600 years that without air resistance, all objects fall the same. Where have you been ?

An object that falls from a height of 'H' hits the ground at a speed of sqrt(2GH).

If 'H' is in meters, then the speed is sqrt(19.6H) meters per second.

If 'H' is in feet, then the speed is sqrt(64.4H) feet per second.