A 34-cm-diameter potter's wheel with a mass of 20 kg is spinning at 180 rpm. Using her hands, a potter forms a pot, centered on the wheel, with a 14 cm diameter. Her hands apply a net friction force of 1.3 N to the edge of the pot. If the power goes out, so that the wheel's motor no longer provides any torque, how long will it take for the wheel to come to a stop in her hands?(adsbygoogle = window.adsbygoogle || []).push({});

Angular acceleration= net Torque/moment of inertia so

(1.3)(.07)/ (20 *.07^2)= .93 radians/second^2

So since angular acceleration=change in angular Velocity/time then:

-.98 = (0-19.8)/change in time so t=19.2 seconds.

Where the initial angular velocity was 19.8 by converting the 180 rev/min to 19.8 radians/sec.

So is my answer of 19.2 seconds correct?

Thank you kindly for your help.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Time it takes for the wheel to stop?

**Physics Forums | Science Articles, Homework Help, Discussion**