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Visualizing a rock passing a window

  • Thread starter drjohn15
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  • #1
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Homework Statement



You are videotaping a birthday party in your dorm room; your dorm window in centered in the frame of your video camera. Suddenly, a rock passes by your dorm window! Assuming the rock was thrown horizontally, and assuming that the rock was traveling in a plane parallel to the window, it is your job to determine, by analyzing your video of the event, from what location the rock was thrown.

When you look out of your window, you are looking due South. From the video, you are able to determine that the rock first came into view at a point on the upper window frame which is 6 cm from the upper right-hand corner of your window. The rock disappeared from view at a point on the lower window frame which is 108 cm from the lower right-hand corner of your window. Your window is 118 cm tall. You are able to determine from the video that the rock was in view for 0.17 seconds.

Homework Equations



N/A

The Attempt at a Solution



So I'm just having a bit of trouble visualizing this scenario. I've drawn a rectangle to represent the window, and its height is 118 cm. I've marked the initial position on the rightmost side, 6cm down from the top side of the window, moving left across the window.

If I'm correct up to this point, then my question is, where exactly is the final position (in terms of a visual representation)? Is it 108 cm leftward from the bottom right corner?


Thanks!
 

Answers and Replies

  • #2
gneill
Mentor
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The top point is on the upper window frame. So it's 6cm left of the top right-hand corner, not down from the corner.

The lower point crosses the bottom of the window frame 108 cm from the bottom right-hand corner.

attachment.php?attachmentid=61284&stc=1&d=1377905761.gif
 

Attachments

  • #3
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The top point is on the upper window frame. So it's 6cm left of the top right-hand corner, not down from the corner.

The lower point crosses the bottom of the window frame 108 cm from the bottom right-hand corner.
Awesome! Thanks a lot!

BTW, how did you make that graph?
 

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