PES 111 General Physics I
Practice Exam 1
Definitions (2 pts each)
1. Acceleration is a change in:
A. Speed
B. Position
C. Direction
D. All of the above
E. Only A and C
F. Only B and C
2. Which SI unit measures weight?
A. The kilogram
B. The pound
C. The newton
D. The erg
3. What are the SI units for the coefficient
of friction?
A. The newton
B. The coloumb
C. Unitless
Concepts (2 pts each)
4. A block rests on an inclined plane. Which of the free-body diagrams below represents this
block?
A.
B.
Weight
Weight
Normal Force
Normal Force
C.
Normal Force
Friction
Friction
D.
Weight
Friction
Normal Force
Weight
Friction
5. What is the direction of the component of acceleration that is turning the direction of the
velocity vector during uniform circular motion?
A. Inward, toward the center
B. Tangent, along the circular path
C. Outward, away from the center
R. Gist
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PES 111 General Physics I
Practice Exam 1
6. Which type of friction occurs only for impending motion?
A. Static
B. Kinetic
C. Rolling
Applications (4-6 pts each)
7. (4 pts) How fast is an object accelerating in SI units if it is accelerating 40 micrometers per
millisecond per millisecond? (micro=10-6, milli=10-3)?
8.
(4 pts) An elevator initially traveling downward at 10 m/s begins to decelerate at a constant
rate of 1 m/s2. How long does it take the elevator to stop?
9. (6 pts) You throw a ball upward against a brick wall with a speed of 20 m/s at an initial angle
of 60o above horizontal. If you are standing 8 m from the base of the wall, how high above the
point you release the ball does the ball hit the wall?
10. (5 pts) A girl swims 2 m/s in still water. She wishes to cross a river of width 100 m flowing
downstream at 1 m/s. She aims at a point 30o upstream and begins to swim. How long does it
take her to swim across?
11. (4 pts) What is the horizontal range of a cannon whose muzzle velocity is 340 m/s and is fired
at a 35o angle above horizontal? (ignore air resistance)
r
12. (5 pts) What magnitude of acceleration will a force of F = (10iˆ − 24 ˆj ) N give to man sitting
in a rolling chair? The combined mass of man and chair is 78 kg. (Ignore any friction)
13. (4 pts) A 60 kg woman stands on a metric scale in an elevator. As the elevator begins to
descend, she notes that the scale reads 400 N. How quickly is the elevator decelerating?
R. Gist
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PES 111 General Physics I
Practice Exam 1
14. (5 pts) Find the magnitude of the displacement between the following Cartesian vectors:
Position 1 (given by the Cartesian vector <12, -5, 0> m)
Position 2 (given by the Cartesian vector <2, 2, 1> m).
15. (6 pts) Three ropes are attached to a tree and are pulled in different directions. The first force
is of magnitude 1000 N in the direction -3/5 iˆ + 4/5 ĵ . The second force is given by (320 iˆ +
1240 ĵ ) N. The third force has magnitude of 600 N, is in the x-y plane and directed 30
degrees below the positive x-axis. What is the resulting force vector on the tree?
16. (6 pts) An external force is exerted horizontally on an 80 kg crate resting on a wooden floor
(μs=.25, μk=.2). What minimum force is required to cause motion? If the force remains the
same after motion begins, what acceleration does the crate experience?
17. (4 pts) What is the maximum angle a metal ramp can be raised before an 8 kg disk of rubber
(radius = 5 cm) begins to slide down it? (Assume the μs of rubber on metal is 0.65).
18. (6 pts) A 1 kg ball at the end of a 0.5 meter string is spun horizontally at the rate of 3
revolutions per second. What is the speed of the ball along the circular path? What is the
tension in the string?
19. (5 pts) What is the apparent weight of a 60 kg man in a car accelerating at 5m/s2 down a
straight, horizontal road?
20. (4 pts) Find the terminal velocity of a falling brick of mass 5 kg and ballistic coefficient of 0.1
N/m2. Assume that the drag force is proportional to speed squared.
21. (6 pts) Find the center of mass of the following system:
Particle 1: m1=2 kg
Particle 2: m2=5 kg
Particle 3: m3=3 kg
R. Gist
x1=1 m
x2=2 m
x3=-1 m
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