View Full Version : Graphs of a vs. t, v vs. t, and d vs. t ???
IamHenry
Sep1-03, 09:15 PM
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
You haven't supplied enough information. What are the relationships between the variables defined by the letters a,t,v,d?
russ_watters
Sep1-03, 09:42 PM
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
Sep1-03, 10:01 PM
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
Sep1-03, 10:26 PM
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.
Hyperreality
Sep1-03, 11:18 PM
v = [inte] a dt
d = [inte] d dt
If it's not a very screwed up graph you can write the equations just by looking at it.
http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/motgraph.html
and Motion equations:
http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html#mot1
HallsofIvy
Sep2-03, 07:43 AM
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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