A spherical weather balloon is leaking helium. The volume, VVV, of the balloon is decreasing at a constant rate.
Show that the rate of decrease of the radius, rrr, of the balloon is inversely proportional to r2r^2r2.
You may use the following formula for the volume of a sphere:
V=43πr3 V = \frac{4}{3}\pi r^3 V=34πr324 exam-style questions on OCR (MEI) A Level Maths 1.9.15 Rates of change with the chain rule (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.