Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A sprinkler throws water m and turns back and forth through . Find the area of the lawn that it waters, and the length of the outer edge of that area.
With in radians, an arc is and a sector has the area . A rolling wheel moves in each turn. For revolutions each minute, rad/s, and a point on the rim moves at .
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.
Step 1. The angle. rad.
Step 2. The area. .
Step 3. The edge. m.
Answer: about of lawn, with an edge of about m.
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