v = 4/3 πr^3
dv/dt = 4πr^2 dr/dt
At t = 120 seconds, v = 480 ft^3
Now you can find r, and you have dv/dt, so use that to find dr/dt.
Helium is pumped into a spherical balloon at a rate of 4 cubic feet per second. How fast is the radius increasing after 2 minutes?
Rate of change of radius (in feet per second) = ??
(i dont know what to with the time given to solve)
1 answer