please help me with this assignment question.(adsbygoogle = window.adsbygoogle || []).push({});

Q: gasoline is pumped from the tank of a tanker truck at a rate of 20L/s. if the tank is a cylinder 2.5 m in diameter and 15 m long, at what rate is the level of gasoline falling when the gasoline in the tank is 0.5m deep? express in exact answer in cm/min [1L=1000 cm^3]

i did:

dv/dt = - 1200000cm^3/min

dv/dt = dv/dh*dh/dt

Vcylinder = pi r^2 l {l=h=length of the cylinder}

r = 125h/50 cm = 5h/2

V= pi(5/2h)^2l

dv/dh = pi 25/2 hl

-1200000 = pi 25/2 (50)(1500) dh/dt

dh/dt = -96/75 pi

i've got a good feeling that this is wrong. please help.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# [chain rule] Related Rates

**Physics Forums | Science Articles, Homework Help, Discussion**