Science:Math Exam Resources/Courses/MATH102/December 2019/Question 10(a)

MATH102 December 2019

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Question 10(a)
A lighthouse is 1 km from the shore. Its beam rotates, taking 20 seconds for one full revolution. (a) In the diagram at right, the dotted line is the beam of light; the solid line is the shortest line from the lighthouse to the shore; and $\theta$ is the angle between those two lines. What is ${\frac {d\theta }{dt}}$, in radians per second? UBC Math 102 2019 Q10

Make sure you understand the problem fully: What is the question asking you to do? Are there specific conditions or constraints that you should take note of? How will you know if your answer is correct from your work only? Can you rephrase the question in your own words in a way that makes sense to you?

If you are stuck, check the hint below. Consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it!

Hint
Note that the beam rotates one full revolution per 20 seconds.

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Solution
Found a typo? Is this solution unclear? Let us know here. Please rate my easiness! It's quick and helps everyone guide their studies. ${\frac {d\theta }{dt}}={\frac {2\pi }{20sec}}={\frac {\pi }{10sec}}$