Interactive Lecture Demonstrations
Click here to download the
Prediction Sheet. Write your name at the top to record your presence and
participation in these demonstrations. For each demonstration
below, write your prediction on this sheet before making any observations. You
may be asked to send this sheet to your instructor.
Demonstration
1: On the left velocity axes below sketch your
prediction of the velocitytime
graph of the man beginning at the origin and moving to the right at a steady
(constant) velocity. On the left
position axes below sketch your prediction of the positiontime graph for the same motion 



Only
after you have made your predictions, open The Moving Man simulation: https://phet.colorado.edu/sims/cheerpj/movingman/latest/movingman.html?simulation=movingman In
the upper left, click on Charts. Then remove the acceleration graph by
clicking on the on the right side of the graph. Use the
Velocity slider to set the velocity at about +2 m/s. Click on to start graphing and click on to stop when he reaches the right barrier. Compare the graphs to your predictions
and explain their shapes. 

Demonstration
2: On the right velocity axes above sketch
your prediction of the velocitytime
graph for the man beginning at the origin and moving to the left at a steady
(constant) velocity. On the right position
axes above sketch your prediction of the positiontime
graph for the same motion. 

Only after you have made your
predictions, test them with The Moving Man simulation. First click on and then to reset everything. Again
remove the acceleration graph by clicking on the on the right side of the graph. Use the
Velocity slider to set the velocity at about 2 m/s. Click on to start graphing and click on to stop when he reaches the left barrier. Compare the graphs to your predictions
and explain any differences with motion toward the right in Demonstration 1. On a positiontime graph what represents
the direction of motion? On a velocitytime graph what represents
the direction of motion? 

Demonstration 3: Sketch on the axes on the right your
predictions for the velocitytime
and accelerationtime graphs
of the man to the right and speeding up at a steady rate. Only after you have made your
predictions, test them with The Moving Man simulation. (NOTE:
Human motion is actually inherently not steady and involves jerks and changes
in the acceleration.) First click on and then to reset everything. Remove the position
graph by clicking on the on the right side of the graph. Use the
Acceleration slider to set the acceleration at about +3 m/s^{2}.
Click on to start graphing and click on to stop when he reaches the right barrier. Compare the graphs to your predictions
and explain any differences. Explain the shapes of your graphs. On
a velocitytime graph what tells you that the object is speeding up at a
steady rate? 

Demonstration 4: Sketch on the axes on the right your
predictions for the velocitytime
and accelerationtime graphs
of the man moving to the right and
slowing down at a steady rate. Only after you have made your
predictions, test them. First click on and then to reset everything. Remove the position
graph by clicking on the on the right side of the graph. Use the
Acceleration slider to set the acceleration at about 3 m/s^{2}. Use
the Velocity slider to set the initial velocity to about + 6 m/s. Click on to start graphing and click on to stop when he momentarily stops moving. Compare the graphs to your predictions
and explain any differences. Explain the shapes of your graphs. How does a
velocitytime graph for slowing down differ from one for speeding up? 

Demonstration 5: There's a very strong wind blowing
toward the left. The man leaps forward and starts running toward the right but the wind slows him down and eventually pushes
him back to the left. Sketch on the axes on the right your predictions for
the velocitytime and accelerationtime graphs of the
man moving to the right, slowing down at a steady rate, coming
to rest momentarily and then moving to the left, speeding up at a
steady rate. Only after you have made your
predictions, test them. First click on and then to reset everything. Remove the position
graph by clicking on the on the right side of the graph. Use the Acceleration
slider to set the acceleration at about 3 m/s^{2}. Use the Velocity
slider to set the initial velocity to about + 6 m/s. Click on to start graphing and click on to stop when he stops at the left barrier. Compare the graphs to your predictions
and explain any differences. Explain the shapes of your graphs. Compare the acceleration
at the moment he reverses his motion to that before and after that time.
Explain why the acceleration has this value. 

Demonstration 6: A cart with low friction is given a push up
an inclined ramp. It rolls up slowing down, reaches its highest point, and
then rolls back down again. Sketch on
the axes on the right your predictions for the velocitytime and accelerationtime
graphs of the cart moving up the ramp, slowing down at a steady
rate, coming to rest momentarily and then moving down the ramp,
speeding up at a steady rate. Only after you have made your
predictions, test them. Download the movie by clicking CartRamp. View the movie and the accelerationtime
and velocitytime graphs. Compare the graphs to your predictions
and explain any differences. Explain the shapes of your graphs. Compare the
graphs to those in Demonstration 5. Explain any similarities. Compare the
acceleration at the moment the cart reverses its motion to that before and
after that time. Explain why the acceleration has this value. 

Demonstration 7: A ball is
tossed straight up in the air. Assuming that air resistance is very small,
sketch on the axes on the right your predictions for the velocitytime and accelerationtime
graphs of the ball moving up, coming to rest momentarily and then
moving down. Only after you have made your
predictions, test them. Download the movie by clicking TossedBall. View the
movie and the accelerationtime and velocitytime graphs. Compare the graphs to your predictions
and explain any differences. Explain the shapes of your graphs. Compare the graphs
to those in Demonstrations 5 and 6. Explain any similarities. Compare the
acceleration at the highest point of the ball's motion to before and after
that time. Explain why the acceleration has this value. 
