nichols (scn285) – Homework #9 – Erskine – (58200)
1
This
printout
should
have
21
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0 points
A rotating rigid body has an angular acceler
ation given in magnitude by
α
(
t
) =
b t
, where
b
is a constant.
What is the angular speed of this body?
1.
ω
(
t
) =
ω
(0)
2
+ 2
b t
(
θ

θ
(0)).
2.
ω
(
t
) =
ω
(0) +
1
3
b t
2
.
3.
ω
(
t
) =
ω
(0) +
1
2
b t
2
.
4.
ω
(
t
) =
ω
(0) +
b t
2
.
5.
ω
(
t
) =
ω
(0) +
α
t
2
.
002
(part 1 of 2) 10.0 points
A
record
has
an
angular
speed
of
18
.
7 rev
/
min.
What is its angular speed?
Answer in units of rad
/
s.
003
(part 2 of 2) 10.0 points
Through what angle does it rotate in 1
.
72 s?
Answer in units of rad.
004
10.0 points
The average angular speed of a fly moving in
a circle is 6.5 rad/s.
How long does the fly take to move through
2.5 rad?
Answer in units of s.
005
10.0 points
A figure skater begins spinning counterclock
wise at an angular speed of 3.7
π
rad/s. Dur
ing a 4.6 s interval, she slowly pulls her arms
inward and finally spins at 8.1
π
rad/s.
What is her average angular acceleration
during this time interval?
Answer in units of rad
/
s
2
.
006
10.0 points
The speed of a moving bullet can be deter
mined by allowing the bullet to pass through
two rotating paper disks mounted a distance
98 cm apart on the same axle.
From the
angular displacement 19
.
5
◦
of the two bul
let holes in the disks and the rotational speed
1223 rev
/
min of the disks, we can determine
the speed of the bullet.
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 Spring '08
 Turner
 Physics, Acceleration, Kinetic Energy, Work, Moment Of Inertia, Rotation, Physical quantities

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