Motion Graphs
Displacement and Velocity
http://www.msu.edu/user/brechtjo/physics/plotXV/plotXV.htmlName ______________________________ Hour _____
The ability to read a graph of motion is essential to the physics student. Graphs are one way to describe the motion of an object and the ability to read the graph is a useful skill for physics students. This Applet program will allow you to visualize the graphs of motion that you assign to an object. We will investigate uniform velocity (no acceleration) and uniform acceleration. The term uniform implies the quantity is constant.
Using your web browser open the web site listed above within the title of this activity. How many graphs are displayed? ________ Name the two types of graphs:
___________________ vs time
___________________ vs time.
Below the two graphs are three quantities, their magnitudes, and buttons to increase/descrease their magnitudes. Identify the three quantities:
X0 = _____________________________ Unit = _____________
V0 = _____________________________ Unit = _____________
a = _____________________________ Unit = _____________
For an object at rest at position 0.0 m (Xo = 0.0 m), its velocity is 0.0 m/s and its acceleration (a = 0.0 m/s2). What does the displacement and velocity graphs look like for this motion. Set the quantities to these values and draw the graphed lines below:
Change the starting position of the object to a positive 50 meters and a -35 meters. Do not change the initial velocity (Vo = 0.0 m/s) or acceleration (a = 0.0 m/s2).
How does the displacement graph change? ____________________________________
How does the velocity graph change? _________________________________________
Before proceeding: Place the initial position value (Xo) back to 0.0 meters.
Part B
Initial Velocity with no Acceleration:
Change the initial velocity (Vo) from 0.0 to several positive values. Select values from 1 to 20 m/s.What is the shape of the displacement vs time graphs for all of these + velocities?
____________________
How is the displacement graph different for a velocity of 5 m/s compared to the graph of 20 m/s?
_________________________________________________________________
Is the displacement vs time graph a straight line? __________________ Is the slope of thedisplacement-time graph a constant value? ________________ What is the slope of displacement-time graph equal to? ____________________________
Change the initial velocity (Vo) from 0.0 to several negative values. Select values from -1 to -20 m/s.
What is the shape of the displacement vs time graphs for all of these negative velocities?
____________________
How is the displacement graph different for a velocity of -5 m/s compared to the graph of -20 m/s?
_________________________________________________________________
Is the displacement vs time graph a straight line? __________________ Is the slope of the displacement-time graph a constant value? ________________ What is the slope of displacement-time graph equal to? ____________________________
Would you agree that the steeper the slope the greater the velocity? _____________
Is constant speed shown as a straight line on a displacement-time graph? _________
Change the initial velocity (Vo) from 0.0 to several positive values. Select values from 1 to 20 m/s. Watch carefully the Velocity-time graph. Answer these questions.
Is the graph of the velocity-time data a straight line? _____________
How are these graphed lines orientated in regards to the x-axis? ____________________
What is the slope of all the velocity-time graphs produced? ______________________
What quantity is the slope of a velocity-time graph a measure of? __________________
What is the acceleration of all these graphs? ______________ m/s2.
Part C
Initial velocity of 0.0 m/s with an acceleration that is not 0.0 m/s2.
Set the Initial Position to 0.0 m and the Initial Velocity to 0.0 m/s.Change the acceleration from +1 to +10 m/s2.
Describe the shape of the displacement-time graphs: __________________________
Describe the shape of the velocity-time graphs: ______________________________
Draw the displacement graphs for an acceleration of 1 m/s2 and 10 m/s2 and the velocity-time graphs for these accelerations. Be sure to indicate which is 1 and 10 m/s2.
For accelerated motion the displacement graph is _______________ for accelerated motion and _________________ for zero acceleration.
Set the Initial Position to 0.0 m and the Initial Velocity to 0.0 m/s.
Change the acceleration from -1 to -10 m/s2.
Describe the shape of the displacement-time graphs: __________________________
Describe the shape of the velocity-time graphs: ______________________________
What quantity does the slope of the velocity-time graph measure? _______________
Part D
Initial velocity of greater than 0.0 m/s with an acceleration that is negative.
Set the velocity to +16 m/s and the acceleration to -4 m/s2.Describe the shape of the displacement graph and the velocity graph.
Draw the graphs below:
What is the speed of the object after 4.0 seconds of motion? ____________
How is this represented by the two graphs?
On the velocity-time graph the slope is ___________________ and the line travels from the first quadrant to the fourth quadrant. When the line is on the x-axis the object has _______________ and when it crosses the x-axis the motion of the object has reversed _________________.
The motion represented on the two graphs is identical. The motion for the first 4 seconds is a curve and a straight line on the two respective graphs. How do you explain this difference for the same motion?
On the displacement-time graph, when is the object at rest (V=0.0 m/s)? ________s
What is the nature of this point location on the d-t graph? _________________
What is the slope of this point on the d-t graph? _______________
Slope on a displacement-time indicates the instantaneous _____________ of the object.