FLEX Physical Science
AP Physics C
Newton's Laws --- Problems and Examples
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
1) The graph in the figure shows the x component of the acceleration of a 2.4-kg
1)
object as a function of time (in ms).
(a) At what time(s) does the x component of the net force on the object reach its
maximum magnitude, and what is that maximum magnitude?
(b) What is the x component of the net force on the object at time t = 0.0 ms and
at t = 4.0 ms?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
2) Two forces act on a 55-kg object. One force has magnitude 65 N directed 59°
clockwise from the positive x-axis, and the other has a magnitude 35 N at 32°
clockwise from the positive y-axis. What is the magnitude of this object's acceleration?
A) 1.3 m/s2
B) 1.7 m/s2
C) 1.1 m/s2
D) 1.5 m/s2
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2)
3) A series of weights connected by very light cords are given an upward acceleration of
4.00 m/s2 by a pull P, as shown in the figure. A, B, and C are the tensions in the
connecting cords. The pull P is closest to
A)
290 N.
B) 690
N.
C)
490 N.
D)
50 N.
E) 200
N.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
4) A construction worker pulls a box of tools on a smooth horizontal floor with a
force of 100 N in a direction of 37.0° above the horizontal. The mass of the box
and the tools is 40.0 kg.
(a) Draw a free-body diagram for the box.
(b) Calculate the acceleration of the box.
(c) How hard does the floor push up on the box?
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4)
3)
5) A locomotive is pulling 19 freight cars, each of which is loaded with the same
5)
amount of weight. The mass of each freight car (with its load) is 37,000 kg. If
the train is accelerating at 0.22 m/s2 on a level track, what is the tension in the
coupling between the second and third cars? (The car nearest the locomotive is
counted as the first car, and friction is negligible.)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
6) A 10,000-kg rocket blasts off from earth with a uniform upward acceleration of 2.00
6)
m/s2 and feels no air resistance. The upward thrust force its engines must provide
during this acceleration is closest to
A) 20,000 N.
B) 78,000 N.
C) 118,000 N.
D) 980,000 N.
7) A block is on a frictionless horizontal table, on earth. This block accelerates at 3.6 m/s2
7)
when a 90 N horizontal force is applied to it. The block and table are then set up on the
moon where the acceleration due to gravity is 1.62 m/s2. A horizontal force of 45 N is
applied to the block when it is on the moon. What acceleration does this force impart to
the block?
A) 2.0 m/
B) 1.8 m/
C) 2.2 m/
D) 1.6 m/
E) 2.3 m/
s2
s2
s2
s2
s2
8) A 50.0-N box is sliding on a rough horizontal floor, and the only horizontal force acting
8)
on it is friction. You observe that at one instant the box is sliding to the right at
1.75 m/s and that it stops in 2.25 s with uniform acceleration. What magnitude force
does friction exert on this box?
A) 490 N
B) 50.0 N
C) 8.93 N
D) 3.97 N
E) 38.9 N
9) The International Space Station has a mass of 1.8 × 105 kg. A 70.0-kg astronaut inside
the station pushes off one wall of the station so she accelerates at 1.50 m/s2. What is
the magnitude of the acceleration of the space station as the astronaut is pushing off the
wall? Give your answer relative to an observer who is space walking and therefore does
not accelerate with the space station due to the push.
A) 4.7 × 10-4 m/s2
B) 5.8 × 10-4 m/s2
C) 3.9 × 10-3 m/s2
D) 1.50 m/s2
E) zero
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9)
10) The following four forces act on a 4.00 kg object:
F 1 = 300 N east
F 2 = 700 N north
F 3 = 500 N west
F 4 = 600 N south
What is the acceleration of the object?
A) 300 N in a direction 26.6° north of west
B) 224 N in a direction 63.4° north of west
C) 2100 N in a direction 26.6° north of west
D) 300 N in a direction 63.4° north of west
E) 224 N in a direction 26.6° north of west
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10)
Answer Key
Testname: NEWTON'S LAWS PHYSICS C PROBLEMS
(b) 12 N, -24 N
1) (a) At 3.0 ms, 48 N
2) C
3) B
4) (a) The box is acted on by the force of gravity which points downward toward the center of the earth. The
normal force is directed toward the box perpendicular to the surface of the floor. The pulling force is
directed away from the box at an angle 37.0 degrees above the horizontal.
(b) 2.00 m/s2
(c) 332 N
5) 140,000 N
6) C
7) B
8) D
9) B
10) E
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