# Circular Motion

• Dec 3rd 2006, 06:43 PM
pre-agitated
Circular Motion
An object is traveling around a circle with the radius of 5cm. If in 20sec the central angle of 1/3 radian is swept out, what is the angular speed of the object? Linear speed?

Here's how I did it. angular speed-->
= π/3/20= π/3*1/20 = π/60 radians/sec. Is that the same as the answer in the book, 1/60?

linear speed-->
=5cm*(1/60)= 1/12 cm/s
the answer in the book is 12m/s.

what did I do wrong?
• Dec 4th 2006, 04:56 AM
topsquark
Quote:

Originally Posted by pre-agitated
An object is traveling around a circle with the radius of 5cm. If in 20sec the central angle of 1/3 radian is swept out, what is the angular speed of the object? Linear speed?

Here's how I did it. angular speed-->
= π/3/20= π/3*1/20 = π/60 radians/sec. Is that the same as the answer in the book, 1/60?

linear speed-->
a) An angle of $\displaystyle \frac{1}{3}$ rad is, like, $\displaystyle \frac{1}{3}$ rad. Why are you sticking the $\displaystyle \pi$ in there? That's your only mistake.