Differential Equation Word Problem

In summary, the conversation discusses finding the velocity and distance traveled of an object with a mass of 70kg that falls from rest under the influence of gravity. The terminal velocity of the object is -20 m/s and air resistance is proportional to velocity. The equation for the distance traveled is x(t)= -40.82e^(-.49t)-20t+A, and in order to solve for A, the initial position of the object (x=0) and initial velocity (v=0) must be taken into account.
  • #1
maherelharake
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An object having mass 70kg falls from rest under the influence of gravity. The terminal velocity of the object is -20 m/s. Assume that air resistance is proportional to velocity.
Q) Find the velocity and distance traveled at the end of 2 seconds.

I got an answer for the velocity, but I am having trouble with the part about distance travelled. I know I just integrate the equation I had for velocity, but I do not know how to solve for the constant that appears after integrating. Thanks!
 
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  • #2
Show us what you have and we'll help you out.
 
  • #3
Sorry this is my first time using the forum. The furthest I got was this equation for the distance...


x(t)= -40.82e^(-.49t)-20t+A


I need help solving for A, so I can solve for the distance after 2 seconds.
 
  • #4
If the object is at x = 0 at t = 0, then x(0) = 0. Use that to solve for A. Also, since it is falling from rest, you know that v(0) = 0 as well.
 
  • #5
So since it is falling from rest, you take the initial position to be 0? That makes sense since it is just used as a reference point, right?
 
  • #6
Or wherever. I didn't see any information in the problem you posted that said it fell from a particular height.
 
  • #7
Exactly. That is why I think it makes sense to take the initial position as 0 since nothing else was given. I will give this a shot. Thanks a lot for your time.
 

FAQ: Differential Equation Word Problem

What is a differential equation word problem?

A differential equation word problem is a type of mathematical problem that involves finding an unknown function based on an equation that relates the function to its derivatives. These problems often involve real-world situations and are used to model a variety of phenomena in science and engineering.

How do you solve a differential equation word problem?

The process of solving a differential equation word problem involves identifying the variables and their relationships, setting up the differential equation based on the given information, and then using integration or other methods to find the solution. It may also involve using initial conditions or boundary conditions to find specific values of the solution.

What are some common applications of differential equation word problems?

Differential equation word problems are used in a variety of fields, including physics, biology, economics, and engineering. They can be used to model population growth, chemical reactions, motion of objects, and many other phenomena.

What skills are needed to solve differential equation word problems?

To solve differential equation word problems, one needs a strong understanding of calculus, specifically derivatives and integrals. It is also helpful to have knowledge of algebra and trigonometry, as well as an ability to interpret and apply mathematical models to real-world situations.

Are there different methods for solving differential equation word problems?

Yes, there are various methods for solving differential equation word problems, including separation of variables, substitution, and using specific formulas for certain types of equations. The method used will depend on the type of equation and the given information in the problem.

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