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most helpful to show how to type into calculator correctly!! plus solutions than

ID: 1301594 • Letter: M

Question

most helpful to show how to type into calculator correctly!! plus solutions thank you!

Because 2? rad = 1 rev, the angular displacement in part (b) corresponds to 2.23 rev. In general, dividing the number of radians by 6 gives a good approximation to the number of revolutions, because 2? ~ 6.

Question If the angular acceleration were doubled for the same duration, by what factor would the angular displacement change?

PRACTICE IT

Use the worked example above to help you solve this problem. A compact disc rotates from rest up to an angular speed of 33.6 rad/s in a time of 0.901 s.

(a) What is the angular acceleration of the disc, assuming the angular acceleration is uniform?
rad/s2

(b) Through what angle does the disc turn while coming up to speed?
rad

(c) If the radius of the disc is 4.45 cm, find the tangential speed of a microbe riding on the rim of the disc.
m/s

(d) What is the magnitude of the tangential acceleration of the microbe at the given time?
m/s2

EXERCISE HINTS:  GETTING STARTED | I'M STUCK!

Use the values from PRACTICE IT to help you work this exercise.
(a) What are the angular speed and angular displacement of the disc 0.320 s after it begins to rotate?


(b) Find the tangential speed at the rim at this time.
m/s

? = rad/s ?? = rad

Explanation / Answer

w0=0
w= 33.6 rad/s
t= 0.901 s
a)
w= w0 + alpha t
alpha = w/t =33.6/0.901 =37.291 rad/s ^2

b)theta = w0t + 1/2* aplha *t^2

theta = 0.5 *37.291 * 0.901 ^2 = 15.1364 rad

c)v= rw
v= 0.0445 *33.6 = 1.4952 m/s

d)a= r* alpha

   = 0.0445 *37.291 = 1.66 m/s^2