A stone is dropped into some water and a circle of radius r is formed and slowly expands. The perimeter of the circle is increasing at 3 m/ s. At the moment the radius is exactly 2m, what rate is the radius of the circle increasing?

Respuesta :

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

The rate at which the radius is changing is [tex]\frac{3}{2\pi }[/tex] m/s.

We have a circle of radius r which is formed when a stone is dropped in it such that the perimeter of the circle is increasing at 3 m/s.

We have to find out at what rate is the radius of the circle increasing.

What is the perimeter of the circle with radius r ?

The perimeter of the circle with radius r is -

Perimeter = 2[tex]\pi[/tex]r

According to the question -

rate of change of perimeter of circle with respect to time is = 3 m/s

Mathematically, we can write it as -

[tex]\frac{dp}{dt} =[/tex] 3 m/s

Differentiating the perimeter with respect to time, we get -

[tex]\frac{d}{dt} 2\pi r =[/tex] 3

2[tex]\pi[/tex] [tex]\frac{dr}{dt}[/tex] = 3

[tex]\frac{dr}{dt}[/tex] = [tex]\frac{3}{2\pi }[/tex] m/s

Hence, the rate at which the radius is changing is [tex]\frac{3}{2\pi }[/tex] m/s.

To solve more questions on rate measurement, visit the link below -

https://brainly.com/question/11965077

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