400
The equation for the speed (not the height) of a ball that is thrown straight up in the air is given by v = 128 – 32t, where v is the velocity (in feet per second) and t is the number of seconds after the ball is thrown. With what initial velocity was the ball thrown? What is the meaning of the slope?
What is every second, the speed decreases by 32 feet per second. Eventually the velocity becomes zero (when the ball reaches its peak), and then becomes negative (when gravity takes over and pulls the ball back down to the ground).