A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 60 cm/s.
a) Express the radius r of this circle as a function of the time t (in seconds).
b) If A is the area of this circle as a function of the radius, A(r(x)) and interpret it.
Please help! I don't even know how to start this problem.
The radius is extending at the rate of 60cm per second.
After 1 second, the radius is 60cm
After 2 seconds, the radius is 2 x 60cm
After 3 seconds, the radius is 3 x 60cm, etc.
So if t represents the time in seconds, the radius is t x 60cm.
This is where the formula comes from.