# Velocity, position, acceleration graph help!

1. Jul 10, 2004

### Physicshelpneeded

im new to this site...so i dont kno whow this works...ANYWAYS....

so you guys know : im 16, taking a college course at mt sac (physics 1)...and im kind of struggling because my math isnt as high as it nees to be for the coruse and because i dont understand soem concepts.

im having trouble with a velocity/time graph problem... the question asks me to determine the distance moved by the object in the time interval from t=0 to t=0.4 (since u guys cant see the graph, i will tell u...the velocity moves from 3.4 to 3.9 in 4 seconds) anyone know how to do this?

the second part to this problem is What additional information do you need to determine the position of the object at t=0.4 s? explain.

CAN ANYONE HELP ME WITH THIS? Thanks guys! (and if you are a girl, girls)

2. Jul 10, 2004

### Blistering Peanut

There are two ways of doing this but you want to do it the graph way. The most important thing to remember is that the area under a velocity/time graph is equal to the distance travelled. So isolate the area under the graph from said interval and divide it up into simple shapes - squares/triangles. It's just very easy geometry from there.

For the second half I'm not sure what they mean by that.

Last edited: Jul 10, 2004
3. Jul 10, 2004

### Physicshelpneeded

thanks for the advice! :) it helped a littel bit...but the problem i have is that the graph is curved....and makes a triangle and an almost-full rectangle...but not an actual one...so how would i find the area of the weird shape? is there a secret way or formula?

and can anyon eelse help me with part 2?

thanx

4. Jul 10, 2004

### rayjohn01

I think Mr peanut already said this , if you must do it graphically ( and the shape is not a rectangle - then you divide the shape into small but measureable sections. Typically use a given small section of time say 0.1 seconds and divide the x axis ( time ) into a number of the sections.In each section measure the y value ( velocity) -- the strip area is thus v*dt . Add up all the sections to get the total area the result is the distance.The accuracy is dependant on the size of dt chosen.
Do you have a typo in the question you said the velocity changes from 3.4 to 3.9 in '4' seconds . did you mean 0.4.

5. Jul 10, 2004