Activity In this activity, you’ll use a video measurement and analysis tool called Tracker to examine the motion of a ball launched vertically from a moving cart. To begin your investigation, open the Howitzer Cart simulation.

Click play () to watch the video. The other video controls allow you to rewind () the video or step forward () or backward () one frame at a time.

Part A
How would you describe the motion of the Howitzer cart (Base)?

How would you describe the motion of the launched ball? Specifically, be sure to include:

In what direction is it launched from the cart?
How do you think its trajectory influenced by the motion of the cart?
How does its trajectory compare with that of a horizontally-launched projectile?

Part C
The graph in the upper-right corner shows horizontal displacement (x) versus time (t) for the ball. What can you conclude from the graph?

Part D
Compare the horizontal displacements of the ball and the cart in the video as they travel along. What do you observe?

Part E
Now compare the x versus t graphs for the ball and the cart. Click on points for the same time on each graph to make quantitative comparisons. Do the graphs confirm your observation in part (d) above?

Part F
Based on your observations of the video and the graphs, what can you say about the horizontal velocities of the ball and the cart? How does this compare with what you learned about a horizontally launched projectile?

Part G
In the graph for the ball, click x (the y-axis label) and select y: position y-component from the dropdown list. From the graph, what can you say about the vertical displacement, y, of the ball? Click graph points to make quantitative observations.

Part H
What can you say about the vertical velocity of the launched ball?

Part I
Now, in the graph for the ball, click y (the y-axis label) and select vy from the dropdown list. This gives the graph of vertical velocity versus time for the launched ball. Does the graph confirm what you predicted about the vertical velocity of the ball? How does the final velocity compare with the initial velocity?

Part J
Summarize the motion of the projectile ball, including its horizontal and vertical motion.