Question

Kristina and Darrin are running around a circular track with the same angular speed. Darrin is running on the inside lane which has radius 40 ft and Kristina is running on the outside lane which has radius 44 ft. If Kristina is running at a rate of 11 ft per second, how fast is Darrin running?

Answer 1

10 ft/s

Explanation:

If Kristina is running at a rate of 11 ft/s and on a circular track with radius of 44 ft, then her angular speed is:

`\omega_K = (v_K)/(r_K) = (11)/(44) = 0.25 rad/s`

And so is Darrin's angular speed. That means his rate is

`v_D = \omega_D * r_D = 0.25 * 40 = 10 ft/s`