Average Velocity Graph: Determine its Values

[Toxage]

Graph :

http://img354.imageshack.us/my.php?image=physicslp1.png

or

http://www.turboimagehost.com/p/766378/physics.JPG.html

Questions:

Determine its average velocity between the following times.

1. t = 25.0 s and t = 30.0s

2. t = 35.0 s and t = 50.0 s

The Attempt at a Solution

average velocity = overall displacement / overall time

1. 6m/5 sec = 1. m/s

2. 10 m / 15 s = 2/3 ms

My teacher uses on online homework program called Webassign, and both of these showed up as wrong. I don't know why. If anyone could help me that would be awesome.

 

[LowlyPion]

Graph :

http://img354.imageshack.us/my.php?image=physicslp1.png

or

http://www.turboimagehost.com/p/766378/physics.JPG.html

Questions:

Determine its average velocity between the following times.

1. t = 25.0 s and t = 30.0s

2. t = 35.0 s and t = 50.0 s

The Attempt at a Solution

average velocity = overall displacement / overall time

1. 6m/5 sec = 1. m/s

2. 10 m / 15 s = 2/3 ms

My teacher uses on online homework program called Webassign, and both of these showed up as wrong. I don't know why. If anyone could help me that would be awesome.

On the first it looks like 8m not 6m. It will likely not think it's good if off by 10%.

Check your sign on the second one.

 

[baba89]

Hello there,

I can provide you with a more detailed explanation of how to determine the average velocity from a graph and why your answers may have been marked as incorrect.

To determine the average velocity between two points on a graph, we need to calculate the slope of the line connecting those two points. This is because the slope of a line represents the rate of change, or in this case, the velocity.

In your first question, the two points are t = 25.0 s and t = 30.0 s. To calculate the slope, we need to find the change in y (displacement) over the change in x (time). In this case, the change in y is 6m (the displacement between the two points) and the change in x is 5s (the time between the two points). Therefore, the slope (or average velocity) is 6m/5s = 1.2 m/s. This is the correct answer.

Similarly, for your second question, the two points are t = 35.0 s and t = 50.0 s. The change in y is 10m and the change in x is 15s, so the slope (or average velocity) is 10m/15s = 0.667 m/s. This is also the correct answer.

It is possible that the online homework program you are using is looking for more precise answers, such as 1.20 m/s and 0.667 m/s. I would recommend checking with your teacher or the program's instructions to see if this is the case. It is also important to make sure you are using the correct units in your calculations (meters for displacement and seconds for time).

I hope this helps clarify the concept of calculating average velocity from a graph. Keep up the good work in your science studies!