You throw a ball at 37° above the horizontal and you want to hit a target on the ground, 20 ft from where you are standing. how fast should you throw the ball? what will be its final velocity?

The given 20 ft in this item is the range of the projectile motion. In dynamics, the equation that relates the range with the initial velocity and the angle is,

                                                Range = (Vo)2sin2θ/g

From the equation, all are given except for the Vo.

Substituting the known values,

                                                20 ft = (Vo)2sin2(37 degress) / 1

The value of Vo is 4.56 ft/s.