Two friends stand 2.0 m apart and look at the same tree across a field…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Two friends stand apart and look at the same tree across a field. Their lines of sight meet at the tree at an angle of . How far away is the tree?
Need a reminder? The key ideaShow
Two points a distance apart (the baseline) see a far object along lines that meet at a small angle . Then
Change degrees with ; one second of arc is of a degree.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. , .
Step 1. Radians. .
Step 2. Distance. .
Answer: About .
Check. The angle is small, so the tree should be many baselines away: is about baselines. Reasonable.
Watch out. Dividing by (degrees) gives , a tree almost on top of you.
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