Question

a spherical balloon is to be deflated so that its radius decreases at a constant rate of 8 cm/min. at what rate must air be removed when the radius is 5 cm?

Answer 1

V = (4/3)πr³

dV/dt = 4πr²(dr/dt)

= 4π((5 cm)²)(-8 cm/min)

= -800π cm³/min

Air must be removed at the rate of 800π cm³/min.