Final Exam
PHY 2130
Monday, April 28, 2003
Please type your name here
Please type your student number here
Instructions:
1.
Do all the questions. Show your work for partial credit.
I must be able to
understand what you have done while I am grading the exam – not when you
explain it to me after the exam is graded and returned.
2.
For each problem:
(a) write down any formula(s) used
(b) justify why you used that particular formula(s)
(c)
show your work!
1.
A 6.0kg object undergoes an acceleration of 2.0 m/s
2
. What is the magnitude of
the resultant force acting on it?
1.
1.2 N
2.
15 000 N
3.
12 N
*
4.
0.15 N
2.
A person takes a trip, driving with a constant speed of 89.5 km/h except for a 22.0
min rest stop. If the person’s average speed is 77.8 km/h, how much time is spent on
the trip?
1.
2.8 h *
2.
2.8 min
3.
20 h
4.
5.6 h
3.
A child throws a marble into the air with an initial speed
v
0
. Another child drops
another marble (of the same weight) at the same instant. Compare the accelerations of
the two marbles while they are in flight. You can neglect air resistance.
Row:
Seat:
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1.
first marble has greater acceleration
2.
second marble has greater acceleration
3.
the accelerations of the two marbles are the same *
4.
impossible to determine with the provided information
4.
A car is stopped for a traffic signal. When the light turns green, the car accelerates,
increasing its speed from 0 to 5.20 m/s in 0.832 s. What are the magnitudes of the
linear impulse and the average total force experienced by a 70.0kg passenger in the
car during this time?
1.
245 kg m/s
2
and 438 N
2.
364 kg m/s
2
and 438 N *
3.
245 kg m/s
2
and 4.38 N
4.
2.45 kg m/s
2
and 4.38 N
5.
A ball is thrown straight up into the air. At what position is the kinetic energy a
maximum? At what position is the gravitational potential energy a maximum?
1.
at the highest point of the trajectory; at the lowest point of the trajectory
2.
at the lowest point of the trajectory; at the highest point of the trajectory *
3.
midway between the highest and the lowest points of the trajectory; at the
highest point of the trajectory
4.
impossible to determine
6.
An electric motor rotating a workshop grinding wheel at a rate of 100 rev/min is
switched off. Assume constant negative angular acceleration of magnitude 2.00 rad/
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 Spring '11
 petrov
 Physics, Kinetic Energy, Work, kg, m/s, Highest point, initial speed v0, object undergoesan acceleration

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