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Extra Credit Problems
Physics 1
Mr. Kiledjian
1)
A rock is dropped from rest into a well.
The sound of the splash is heard 3.25 seconds
after the rock is released from rest.
The speed of sound in air is 336 m/s.
How far below
the top of the well is the surface of the water?
(Chapter 2, #60)
Answer:
H = 47.39 meters
2)
Setting a new world record in a 100 meter race, Maggie and Judy cross the finish line
in a dead heat, both taking 10.2 seconds.
Accelerating uniformly, Maggie took 2 seconds
and Judy took 3 seconds to attain maximum speed, which they maintained for the rest of
the race.
a) What was the acceleration of each sprinter?
b) What were their respective
maximum speeds?
c) Which sprinter was ahead at the 6 second mark, and by how
much?
(Chapter 2, #53)
Answer:
a) 5.43 m/s
2
and
3.83 m/s
2
b) 10.9 m/s
and
11.5 m/s
c) Maggie
by
2.62 meters
3)
The acceleration of a marble in a certain fluid is proportional to the speed of the
marble squared, and is given by a = 3.00v
2
for v > 0.
If the marble enters this fluid with
a speed of 1.50 m/s, how long will it take before the marble’s speed is reduced to half of
its initial value?
Answer:
.222 seconds
4)
A pirate has buried his treasure on an island with five trees, located at the following
points: A (30 m, 20 m), B (60 m, 80 m), C (10 m, 10 m), D (40 m, 30 m), and E
(70 m, 60 m).
His ship’s log instructs you to start at tree A and move toward tree B, but
to cover only half the distance between A and B.
Then move toward tree C, covering one
third the distance between your current location and C.
Next, move toward D, covering
one fourth the distance between where you are and D.
Finally, move towards E, covering
one fifth the distance between you and E, stop, and dig.
What are the coordinates of the
point where his treasure is buried?
(Chapter 3, #59)
Answer:
(10 m, 16 m)
5)
A skier leaves the ramp of a ski jump with a velocity of 10.0 m/s, 15 degrees above
the horizontal (this is actually a Winter Olympics sport).
The slope of the mountain is
inclined at 50 degrees and air resistance is negligible.
Find
a) the distance from the
ramp to where the jumper lands
b) the velocity components just before the landing.
(Chapter 4, #59)
Answer:
a)
43.2 meters
b)
v
x
= 9.66 m/s
v
y
= 25.5 m/s
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View Full Document6) An enemy ship is on the east side of a mountain island.
The enemy ship has
maneuvered to within 2,500 meters of the 1,800 meterhigh mountain peak and can shoot
projectiles with an initial speed of 250 m/s.
If the western shoreline is horizontally 300
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 Summer '08
 Kiledjian
 Physics

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