Calc I - Finding average velocity using integration

In summary, the problem is to find the average velocity of two cars over a given time interval. By integrating the velocity function, the position function can be found and the distances traveled by each car can be estimated. The car with the larger region under the curve (from the curve to the x-axis) will have a higher average velocity and therefore travel farther. To solve this problem, you will need to calculate the average value of the velocity function using integration.
  • #1
opticaltempest
135
0
Can I use integration to show why car 2 traveled farther than car 1 over a given time interval?

Here is some of the problem,

I have the following graph of two different velocity functions
for two cars.

http://img97.imageshack.us/img97/5696/graph1kv.jpg"

The viewing window of this graph is x from 0 to 30
and y from 0 to 100.

After integrating the velocity function I found the position function.
Estimating the distances traveled by both cars from time t = 0
to time = 30 I find,

Car 1 whose velocity function is the thin line on the graph
traveled approximately 964.11 feet.

Car 2 whose velocity function is the thick line on the graph
traveled approximately 1977.9 feet.

By looking at the graph it is obvious that the thick line has
a larger region under the curve (from the curve to the x-axis) than
the thin line.

Is it possible to integrate from 0 to 30 on each velocity function and show that the larger regions under the curve correspond to a higher average velocity over time interval 0 to 30 which is why car 2 traveled farther? Am I on the right track about dealing with the velocities of the cars? Should I also consider their acceleration as being a reason for why car 2 traveled farther?

I need explain why car 2 traveled farther. Is it possible to use integration to find average velocity?

In the original problem velocity is given every 5 seconds from 0 to 30 for each car. I could find the secant line over each 5 second interval and average those secant lines to find the approximate average velocity from time 0 to 30, correct? If possible I want to try to use integration to solve this.

Thanks
 
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  • #2
You have two velocity graphs and you want to find the average velocity. Your instincts are correct to integrate, but it's not just integrating from 1 to 30. Calculating the average value of a function, f(x), from a to b can be done as follows:

[tex]A(x)=\frac{1}{b-a}\int_{a}}^{b}f(x)dx[/tex]
 

1. What is the formula for average velocity using integration?

The formula for average velocity using integration is v_avg = 1/b-aab v(t) dt. This means that the average velocity is equal to the integral of the velocity function, divided by the time interval between two points (a and b).

2. How do you find the velocity function in order to use integration for average velocity?

In order to find the velocity function, you need to first find the position function. Then, you can take the derivative of the position function to get the velocity function. This is necessary because the integral of the velocity function gives the change in position, which is needed for calculating average velocity.

3. Can you explain the concept of Riemann sums in the context of finding average velocity using integration?

Riemann sums are used to approximate the area under a curve. In the context of average velocity, Riemann sums are used to approximate the change in position over a small time interval. By taking smaller and smaller time intervals, the Riemann sum becomes more accurate and approaches the exact value of the integral, giving the average velocity.

4. What are the limitations of using integration to find average velocity?

One limitation is that it assumes the velocity is constant over the entire time interval. This may not be true in cases where the velocity is changing rapidly. Another limitation is that it only gives the average velocity, and not the instantaneous velocity at a specific point in time.

5. How is average velocity different from instantaneous velocity?

Average velocity is the average rate of change of position over a certain time interval. It gives an overall picture of an object's motion during that time. Instantaneous velocity, on the other hand, is the velocity at a specific point in time. It gives the exact velocity of an object at a particular moment.

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