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| A screenshot of our motion graphs. |
We've been studying motion this week in class. We used an iOS app called Vernier Video Physics ($2.99 on the App Store) to analyze the motion of a basketball. Specifically, we tossed a basketball straight up into the air. The top graph shows vertical position vs. time, and the bottom graph shows the basketball's vertical velocity vs. time.
In the comments, answer one of the following questions (just one so other students will have a chance too):
- How high above the ground was the basketball when it was first thrown?
- Estimate the highest height attained by the basketball.
- With what speed was the basketball initially launched (when it first left the student's hand)?
- How long was the basketball in flight before it reached the apex of its trip?
- In class, we calculated the slope of the bottom graph to be about 8.8. What are the correct units for this slope?
Finally, let's get lots of comments on this question:
- The acceleration of gravity near the Earth's surface is known to be 9.8 m/s/s which is a little higher than the acceleration measured by our experiment. Why does it make sense that our particular basketball's acceleration was a little lower than ideally expected?
The basketball reached its highest height at about 4meters. It makes sense that this basketballs acceleration was lower than expected because, when doing a real life experiment, there are certain factors that can change the outcome you get. Factors such as wind speed and direction, human error, and air resistance can cause differences in the theoretical and experimental outcomes. The basketballs acceleration may have been lower than expected due to a margin of error that must be accounted for.
ReplyDeleteI am going to give question number 4 a shot and say that the ball was in flight for about 3.25 or 3.3 seconds before it reached the apex of its trip.
ReplyDeleteTo answer question 5, I believe that the correct units for the slope of the bottom graph (8.8) is m/s/s because the graph is showing velocity times time. And that is acceleration. Acceleration is the change in velocity over time. And that is exactly what that graph is showing! The basketball might be off the acceleration of gravity because there are certain things that could change the number, like Alana said, or maybe the math was a little off or it may have something to do with the fact that the blab all did not start at zero when it was thrown.
ReplyDeleteNice job with the comments this week. You are all correct. When I did the calculation for the ball's acceleration, I found it to be about 8.9 m/s/s. My guess is the biggest factor making this number a little smaller than expected is the air resistance acting on the basketball.
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