Physics 201  MWF10:20  Fall 1993 (Ford)
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Exam I  Chapts. 1-5 in SZY College Physics
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Show all your work. Partial credit will be given if earned. Write your 
answers in the blanks provided.
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(14 pts) 1. What are the magnitude and direction
(angle <img src="greek/theta.gif"> measured
counterclockwise from the +<i>x</i>-axis)
of the vector <b>C</b> that is
the sum of the vectors <b>A</b> and <b>B</b> shown in the sketch 
(<b>C</b> = <b>A</b> + <b>B</b>)?  Vector <b>A</b> has magnitude 4.0 m and
vector <b>B</b> has magnitude 8.0 m.
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<img src="fig/i931.gif">
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Ans. <i>C</i> = __5.37 m__
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<img src="greek/theta.gif"> = __243&#176 __
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(20 pts) 2. At the instant the traffic light turns green, a car stopped at the
intersection starts forward with a constant acceleration of
2.0 m/s<sup>2</sup>. At the same instant a truck traveling in the same
direction at a constant speed of 6 m/s passes the car. If
the truck continues traveling with constant speed,
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a) what distance does the car travel before it overtakes and passes the truck?
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Ans. __36 m__
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b) how fast is the car traveling when it passes the truck?
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Ans. __12 m/s__
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(20 pts) 3. A 6.0 kg box is placed on a frictionless incline that
slopes upward at 37&#176 .  What magnitude of horizontal force <b>F</b>
is required to push the box up the incline at constant speed? (Note
that </i>F</b> is horizontal and <b>not</b> parallel to the incline.)
<br>
<img src="fig/i933.gif">
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Ans. __44.3 N__
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(22 pts) 4. A hammer slides off a roof that slopes downward at an angle of 
37&#176 . It leaves the edge of the roof with a velocity that is at
37&#176  below the horizontal and that has magnitude <i>v</i><sub>0</sub>
The edge of the
roof is a height <i>h</i> above the ground. The hammer strikes the ground 2.0 s
after leaving the edge of the roof. The hammer lands a distance of 20 m
from the base of the building.
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a) What is the initial speed <i>v</i><sub>0</sub> of the hammer?
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Ans. __12.5 m/s__
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b) What is the height <i>h</i> of the edge of the roof above the ground?
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Ans. __34.6 m__
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(24 pts) 5. The system shown in the sketch consists of two hanging blocks
connected by two light ropes to a 10-kg block that is on a horizontal
tabletop. One hanging block has mass 5 kg and the other block has unknown
mass <i>m</i>. The coefficient of kinetic friction between the 10-kg block
and the
tabletop is &#181<sub>k</sub> = 0.2. When the system is released the 5 kg
block accelerates upward with magnitude of acceleration 
<i>a</i> = 2 m/s<sup>2</sup>.
<br>
<img src="fig/i935.gif">
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a) While the blocks are moving, what is the tension
<i>T</i><sub>1</sub> in the rope connected to the 5 kg block?
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Ans. <i>T</i><sub>1</sub> = __59 N__
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b) While the blocks are moving, what is the tension
<i>T</i><sub>2</sub> in the rope connected to the block that has mass <i>m</i>?
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Ans. <i>T</i><sub>2</sub> = __98.6 N__
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c) What is the mass <i>m</i>?
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Ans. <i>m</i> = __12.6 kg__