A stone is dropped into some water and a circle of radius r is formed and slowly expands. The perimeter of the circle is increas

Question

3 years ago

15

ing at 3 m/ s. At the moment the radius is exactly 2m, what rate is the radius of the circle increasing?

2 answers:

Mazyrski [523] · Answer 1 · 2022-08-21T12:32:28+03:00

3 0

I believe it would be 6 due to the radius being a half of the actual circumfrence

zimovet [89] · Answer 2 · 2022-08-21T13:53:52+03:00

3 0

The relation between perimeter and radius is P = 2 pi r

dP/dr = 2pi

dP/dt = 3

when r = 2 dr/dt = dP/dt * dr/DP = 3 * 1/2pi = 0.477 m/s