posted by Tammy
A bike wheel rotates uniformly through 2 revolutions in 3 seconds.
a) what is the period of the wheel's rotation?
b) what is the frequency of the wheel's rotation? (in Hertz)
c) what is the angular speed of the wheel(provide answer in degrees, radians and revolutions)
How would I figure out part c? also did I do a) and b) correctly?
part c: doesn't it rotate 2Pi in one period?
a: How did you get it 3 rev per 2 seconds? that is not given.
B, of course is wrong because of period is wrong.
Well isn't T = to the time of one revolution? So I took 3rev/2s to get 1.5s
Tammmy. IT did not complete 3 revolutions. Reread the problem.
Bob is right, it did not complete 3 revolutions, but the answer for a) is still correct, for the wrong reason.
Wheel completes 2 revolutions in 3 seconds. Period is amt of time to complete 1 revolution. Think of it as a distance problem.
Distance (# of revolutions) = Rate (revolutions/second) * Time (seconds)
So 1 revolution = (2 revolutions per 3 seconds) * Time
Time = (1 rev)/(2 revs/3 seconds) = 3/2 seconds, or 1.5 seconds
For part C, just divide the distance around the circle by the period 1.5s
i) 360 degrees/1.5 sec = 240 degrees/sec
ii) 2pi radians/1.5 sec = (4/3)pi rad/sec
iii) 1 revolution/1.5 sec = 2/3 rev/sec