Try the fastest way to create flashcards
Question

A track star runs a 400-m race on a 400-m circular track in 45 s. What is his angular velocity assuming a constant speed?

Solution

Verified
Step 1
1 of 2

ω=dθdt=ΔθΔt=2π45=0.14 rads\begin{align*} \omega&=\dfrac{d\theta}{dt} \\ &=\dfrac{\Delta \theta}{\Delta t} \\ &=\dfrac{2\pi}{45} \\ &=0.14 \text{ } \dfrac{\text{rad}}{\text{s}} \end{align*}

Since the perimeter of the circular track is 400 m400\text{ m}, and the distance covered by the runner is also 400 m400\text{ m}, this means that the runner covered precisely one circumference, hence the angle covered is 2π rad2\pi \text{ rad}. We proceed to use the definition of angular speed to calculate ω\omega. Note that dθd\theta and dtdt are equal to Δθ\Delta \theta and Δt\Delta t respectively, because the rotation occurs at constant speed.

Create a free account to view solutions

Create a free account to view solutions

Recommended textbook solutions

Physics for Scientists and Engineers: A Strategic Approach with Modern Physics 4th Edition by Randall D. Knight

Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

4th EditionISBN: 9780133942651 (8 more)Randall D. Knight
3,508 solutions
Mathematical Methods in the Physical Sciences 3rd Edition by Mary L. Boas

Mathematical Methods in the Physical Sciences

3rd EditionISBN: 9780471198260 (1 more)Mary L. Boas
3,355 solutions
Fundamentals of Physics 10th Edition by David Halliday, Jearl Walker, Robert Resnick

Fundamentals of Physics

10th EditionISBN: 9781118230718 (3 more)David Halliday, Jearl Walker, Robert Resnick
8,971 solutions
University Physics, Volume 1 1st Edition by Jeff Sanny, Samuel J Ling, William Moebbs

University Physics, Volume 1

1st EditionISBN: 9781938168277Jeff Sanny, Samuel J Ling, William Moebbs
1,471 solutions

More related questions

1/4

1/7