Example: A ball is thrown straight up with a velocity given by v(t) = 32t + 20 ft/s, where t is measured in seconds. Find and interpret ∫v(t) dt.
Explanation: Using the Second Fundamental Theorem of Calculus, we have
∫(32t + 20) dt = 16t^2 + 20t + C.
Thus, if a ball is thrown straight up into the air with velocity v(t), the height of the ball, 1 second later, will be 4 feet above the initial height. Note that the ball has traveled much farther. It has gone up to its peak and is falling down, but the difference between its height at t=0 and t=1 is 4 ft.