420 rev/min = 420 * 2 pi /60 = 44 radians/second
120 rpm = 12.6 rad/s
alpha = (12.6 - 44 ) /4 = -7.86 radians/s^2 (part A)
angle = initial omega t + (1/2) alpha t^2
angle = 44 (4) - (1/2)(7.86)(16)
= 113 radians
113/2pi = 18 revolutions
18 * 2 pi r =18 *2 pi * .2 = 22.6 cm
but I think you mean meters, not centimeters
A wheel on a moving car slows uniformly from 420 rpm to 120 rpm in 4 sec.
A. What is the angular acceleration of the wheel?
B. What is the angular displacement? How many revolutions?
C. How far does the car travel if the radius of the wheel is 0.20cm?
1 answer
3 answers