Transcript Chapter 6 Review

Chapter 6 Review
Projectile Motion
And
Centripetal acceleration
Topics Tested on the Exam
Projectile Motion
Problems
Concepts
Centripetal Acceleration
Problems
Concepts
1
6
10
14
2
7
11
15
3
8
12
16
4
9
13
17
5
Projectile 1
A golfer is teeing off on a 170.0 m long, level,
par 3 hole. The ball leaves with a velocity of
40.0 m/s at 50.0o to the horizontal. Assuming
that she hits the ball on a direct path to the
hole, how far from the hole will the ball land?
(no bounces or rolls)
Distance from the hole ≈ 9.2 m
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Projectile 2
A canon ball fired horizontally from a cliff has a
velocity directed at 60o below horizontal when
it hits the ground 3.0 seconds later. How high
was the cliff?
Cliff height ≈ 14.7 m
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Projectile 3
A flare gun launches a bright, glowing flare at 60
m/s at an 80° angle above horizontal. How
high does it go?
Max height ≈ 178 m
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Projectile 4
A human cannonball is shot from a cannon at 25
m/s at an angle of 22°. If he leaves the
cannon at ground level and lands in a net also
at ground level, how far does the person travel
along the horizontal
Range ≈ 44.3 m
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Projectile 5
A lacrosse player throws the ball down field to a
teammate. The ball leaves her stick 1.2 meters
above the ground, with a velocity of 13 m/s at
an angle of 38 degrees to the horizontal. The
ball is caught 12.5 meters down the field.
What is the height of the ball when it is
caught?
Height of catch ≈ 3.67 m
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Projectile 6
A rock is thrown up off a cliff. Where is the
vertical velocity zero?
The vertical velocity is zero as the
rock reaches its maximum height.
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Projectile 7
A paper rocket is launched vertically from the
ground and then lands on the ground.
Compare the speed of the rocket at the end of
the trip and the beginning of the trip (ie, is
one bigger, smaller, equal?)
The beginning and ending speeds will
be the same. (yet opposite in direction)
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Projectile 8
A rock is thrown from a window. Compare the
speed of the rock horizontally at the end (just
before it hits the ground) and the beginning of
the trip (ie, is one bigger, smaller, equal?)
The horizontal speeds at the
beginning and the end will be equal.
Since horizontal acceleration is zero
the velocity will remain constant.
back to beginning
Projectile 9
True or False. A hunter in a tree stand is at the
same height as a squirrel. The hunter fires a
bullet at a positive angle in order to hit the
squirrel. The maximum height is achieved half
way through the bullets trajectory.
True. (only because the bullet starts
and ends at the same height)
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Centripetal 10
A CD spins with a frequency of 1800 revolutions
per minute, what is the period of the spin of
the compact disc?
Period = 1/30 sec ≈ 0.0333 sec
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Centripetal 11
You can spin a pizza dough overhead with a
frequency of 60 revolutions per minute. Find
the linear speed of a pepperoni 10 cm from
the center of the pizza.
Velocity ≈ 0.63 m/sec
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Centripetal 12
The earth turns on its axis approximately once
every 24 hours. The radius of the earth is
6.38 x106 meters. If something brought the earth
to a screeching halt, how fast would people on
the equator fly off the earth.
The velocity of a person standing on
the equator is ≈ 464 m/sec.
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Centripetal 13
A 0.100 kg mass is attached to a string 75 cm
long and swings in a horizontal circle,
revolving once every 0.80 s. What is the
centripetal acceleration of the mass.
Acceleration ≈ 46.26 m/sec2
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Centripetal 14
Will the centripetal force and the centripetal
acceleration work in the same direction or
different directions? What equation shows
the relationship between the two?
Always the same direction as one another.
F=ma
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Centripetal 15
What provides the force required to keep a
curving vehicle on the road?
The friction between the road and the tires.
(static friction or kinetic friction?)
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Centripetal 16
What provides the force required to keep a
bucket full of water from spilling as it swings
upside down?
The pulling on the handle from the person
swinging the bucket.
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Centripetal 17
What acceleration is required to keep the water
in a bucket as it swings upside down?
Any centripetal acceleration greater than
the acceleration of gravity.
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