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Cutnell/Johnson
Physics 8th edition
Classroom Response System Questions
Chapter 5 Dynamics of Uniform Circular Motion
Interactive Lecture Questions
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View Full Document 5.1.1. An airplane flying at 115 m/s due east makes a gradual turn while maintaining its speed
and follows a circular path to fly south.
The turn takes 15 seconds to complete.
What is
the radius of the circular path?
a)
410 m
b)
830 m
c)
1100 m
d)
1600 m
e)
2200 m
5.2.1. A ball is whirled on the end of a string in a horizontal circle of radius
R
at constant
speed
v
.
By which one of the following means can the centripetal acceleration of the
ball be increased by a factor of two?
a)
Keep the radius fixed and increase the period by a factor of two.
b)
Keep the radius fixed and decrease the period by a factor of two.
c)
Keep the speed fixed and increase the radius by a factor of two.
d)
Keep the speed fixed and decrease the radius by a factor of two.
e)
Keep the radius fixed and increase the speed by a factor of two.
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View Full Document 5.2.2. A steel ball is whirled on the end of a chain in a horizontal circle of radius
R
with a
constant period
T
.
If the radius of the circle is then reduced to 0.75
R
, while the period
remains
T
, what happens to the centripetal acceleration of the ball?
a)
The centripetal acceleration increases to 1.33 times its initial value.
b)
The centripetal acceleration increases to 1.78 times its initial value.
c)
The centripetal acceleration decreases to 0.75 times its initial value.
d)
The centripetal acceleration decreases to 0.56 times its initial value.
e)
The centripetal acceleration does not change.
5.2.4. A truck is traveling with a constant speed of 15 m/s.
When the truck follows a curve
in the road, its centripetal acceleration is 4.0 m/s2.
What is the radius of the curve?
a)
3.8 m
b)
14 m
c)
56 m
d)
120 m
e)
210 m
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View Full Document 5.3.1. A boy is whirling a stone at the end of a string around his head.
The
string makes one complete revolution every second, and the tension in
the string is
F
T.
The boy increases the speed of the stone, keeping the
radius of the circle unchanged, so that the string makes two complete
revolutions per second.
What happens to the tension in the sting?
a)
The tension increases to four times its original value.
b)
The tension increases to twice its original value.
c)
The tension is unchanged.
d)
The tension is reduced to one half of its original value.
e)
The tension is reduced to one fourth of its original value.
600 N.
One end of the rod is connected to a motor and a 12kg
spherical object is attached to the other end.
When the motor is turned
on, the object moves in a horizontal circle with a radius of 6.0 m.
If
the speed of the motor is continuously increased, at what speed will the
rod break?
Ignore the mass of the rod for this calculation.
a)
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This note was uploaded on 09/21/2011 for the course PHY 1500 taught by Professor Staff during the Spring '09 term at University of Central Florida.
 Spring '09
 Staff

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