# Graphs of a vs. t, v vs. t, and d vs. t ?

#### IamHenry

Graphs of a vs. t, v vs. t, and d vs. t ???

Plese help !!

I am given a graph of a vs. t
How do i use it to determine the other graphs:
v vs. t
d vs. t

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#### mathman

You haven't supplied enough information. What are the relationships between the variables defined by the letters a,t,v,d?

#### russ_watters

Mentor
If you have the equations, just plug in a few points and go.

If you have one equation, you integrate to get the others... but like mathman said, you haven't given us enough information.

#### IamHenry

i am not given any equations
i am only given the graph of a vs. t
btw
a=acceleration
t=time
v=velocity
d=displacement
plz help
thx

#### Integral

Staff Emeritus
Gold Member
You need to use the basic relationships between the quanities.

a= dv/dt => The acceleration determines the slope of the velocity graph. So a constant acceleration line means an increasing velocity, Acceleration = 0 means a constant velocity. You must study the graphs you are given and piece together the various graphs.

Remember that v = dx/dt so you can do the same thing with the velocity line to create a displacement graph.

With that said this is off to homework.

v = [inte] a dt

d = [inte] d dt

#### Sonty

If it's not a very screwed up graph you can write the equations just by looking at it.

#### HallsofIvy

Homework Helper
Probably what you want for this is the fact that the integral is the area under the curve.

Given a graph for a(t), estimate the area under the curve from 0 to t for a number of different values of t. That will give the graph for v(t). It is probably enough to remember things like: if the graph of a(t) is above a=0, then v(t) is increasing, if below, then v(t) is decreasing. if the graph of a(t) is horizontal, then v(t) increases (or decreases) linearly with slope given by the a value.

Once you have a rough graph for v(t), x(t) is the area under that curve. Repeat the process to get a graph of x(t).

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