A potter is trying to determine the inertia of a pottery bowl. She notices that without the bowl, friction causes the pottery wheel to slow from 60rpm to a stop in 10s. With the bowl on top, the wheel stops in 14s. The wheel has a radius of .25m and a mass of 4kg. Determine the inertia of the bowl. Assume friction is the same with and without the bowl.
Given that,
Ww = 60 rpm = 6.283 rad/s
t = 10 s
From the equation of rotational motion,
wf = w - *t
0 = 6.283 - *10
= 0.628 rad/s^2
With the bowl on top,
Let, angular speed = w'
w2 = w' - *t
w' = 0.628*14
w' = 8.796
moment of inertia of wheel,
lw = mr^2 = 4*(0.25)^2
lw = 0.25 kg.^2
From conservation of angular mommentum,
l1*w1 = l2*w2
0.25*6.283 = l * 8.796
l = 0.175 kg.m^2
Get Answers For Free
Most questions answered within 1 hours.