A heavy object is dropped from a vertical height of 8.0 m. What is its speed when it hits the ground?

What do you know:

d=-8.0mm (starts higher and ends lower so it is negative)

Vi=0m/s (because it was dropped, not thrown)

A=-9.8m/s^2 (gravity)

Vf=?

Use the equation:

Vf^2=Vi^2+2A (d)

Vf^2=2 (-9.8) (-8.0)

Vf^2 = 156.8 - - >find the square root of this

Final answer: Vf = 12.5m/s