9.5 - Sample problem: a clock
Think about the movement of the minute hand over the course of an hour. Be sure to consider the direction!
VariablesWhat is the strategy?- Calculate the angular displacement.
- Convert the elapsed time to seconds.
- Use the angular displacement and time to determine the angular velocity and angular acceleration.
Physics principles and equationsDefinition of angular velocityDefinition of angular accelerationStep-by-step solution
We start by calculating the angular displacement of the minute hand over 1.00 hour. We then calculate the angular velocity.The angular displacement is calculated in step 1, and the angular velocity in step 5. Since the angular velocity is constant, the angular
acceleration is zero.Over the course of 1.00 hour, what is
(a) the angular displacement, (b) the
angular velocity and (c) the angular
acceleration of the minute hand?
elapsed time ǻt= 1.00 h
angular displacement ǻș
angular velocity Ȧ
angular acceleration Į
Step Reason
1. ǻș = –2ʌ rad minute hand travels clockwise one revolution
2. convert to seconds
3. definition of angular velocity
4. substitute
5. Ȧ = –1.75×10í^3 rad/s evaluate
(^180) Copyright 2007 Kinetic Books Co. Chapter 09