Register to reply

Differential Equation with growth

by DM1984
Tags: differential, equation, growth
Share this thread:
Nov12-12, 07:52 PM
P: 6
So, I have a differential equation with growth problem. It is a dm/dt function and I need to get it to dD/dt, change in diameter with time.

here is the original functon,
dm/dt= (pi/4)(D)^2* (V(D))*(LWC)*E

LWC = 2
V(D) = 343D^0.6 m/s

it starts from a diameter of 1mm and grows to 5mm and I need to find the time it takes.

I'm not asking for anyone to solve the problem and give me a final solution, but I need help in getting the dD/dt function.

I thought this was it.... but its not:
multiplying by dt ___ dm = [(pi/4)(D)^2 * (v) * (LWC) (E)] dt

integrating ___ m = [(pi/4)(D)^2 * (v) * (LWC) (E)] t

dividing ___ m / [(pi/4)(D)^2 * (v) * (LWC) (E)] = t

Phys.Org News Partner Science news on
New model helps explain how provisions promote or reduce wildlife disease
Stress can make hard-working mongooses less likely to help in the future
Grammatical habits in written English reveal linguistic features of non-native speakers' languages
Nov13-12, 07:53 AM
Sci Advisor
PF Gold
P: 39,297
I don't see how you can possibly change from dm/dt to dD/dt without knowing how m is related to D.
Nov13-12, 09:06 AM
P: 6

Register to reply

Related Discussions
Exponential growth differential equation Calculus & Beyond Homework 5
Differential equation of growth & decay Calculus & Beyond Homework 4
Differential Equation, exponential growth Calculus & Beyond Homework 3
Differential equation for exponential growth Calculus & Beyond Homework 5