Disregarding air resistance, what is the speed of a ball dropped from 12 feet just before it hits the ground? (Use 1 ft = 0.30 m, and use g = 9.8 m/s2.)

This is an example of a free-fall problem. This can be solved using the following free-fall equation:

Let: V = velocity; g = acceleration due to gravity (9.8 m/s^2); h = 12 feet

V^2 = 2gh or V = √ (2gh)

It is important that we use similar units of measurement, so let us convert the height from feet to meters using the given relationship 1 ft = 0.30m.

12 feet x 0.30m = 3.6m

Subsituting the given values to the formula:

V = √ (2gh)

V = √ (2 x 9.8 x 3.6)

V = √ (70.56)

V = 8.4 m/s | This is the speed of the ball dropped just before it hits the ground