Practice Exam #1 Chapters 1-3
PS113 Introductory Physics I
Dr. Darrel Smith
May 19, 2014
Chapter 1
Circle the correct answer:
1. The mass of a raindrop is 4 milligrams. Which one of the following statements indicates
the correct mass of the raindrop in grams?
A) The raindrop has a mass of 4 × 106 grams.
B) The raindrop has a mass of 4 × 10–3 grams.
C) The raindrop has a mass of 4 × 10–1 grams.
D) The raindrop has a mass of 4 × 103 grams.
E) The raindrop has a mass of 4 × 10–6 grams.
Ans: B
2. The surface of a lake has an area of 15.5 km2. What is the area of the lake in m2?
A) 1.55 × 104 m2
B) 1.55 × 105 m2
C) 1.55 × 106 m2
D) 1.55 × 107 m2
E) 1.55 × 108 m2
Ans: D
3. Three sticks are arranged to form a right triangle. If the lengths of the three sticks are 0.47
m, 0.62 m and 0.78 m, what are the three angles of the triangle?
A) 90°, 45°, and 45°
B) 90°, 62°, and 28°
C) 90°, 59°, and 31°
D) 90°, 48°, and 42°
E) 90°, 53°, and 37°
Ans: E
4. A surveyor wants to find the distance across a river. A stake is placed on each bank of the
river as shown in the figure. She measures a distance of 30.0 m from one stake to another on
the same side of the river, thus finding the third vertex on a right triangle. She then measures
the angle  and finds it equal to 75.9°. What is the distance across the river?
A)
B)
C)
D)
E)
89.2 m
15.3 m
119 m
268 m
29.0 m
Ans: C
5. Two displacement vectors of magnitudes 21 cm and 79 cm are added. Which one of the
following is the only possible choice for the magnitude of the resultant?
A) 0 cm
B) 28 cm
C) 37 cm
D) 82 cm
E) 114 cm
Ans: D
6. A force, , of magnitude 2.0 N and directed due east is exerted on an object. A second force
exerted on the object is = 2.0 N, due north. What is the magnitude and direction of a third
force, , which must be exerted on the object so that the resultant force is zero?
A) 1.4 N, 45° north of east
B) 1.4 N, 45° south of west
C) 2.8 N, 45° north of east
D) 2.8 N, 45° south of west
E) 4.0 N, 45° east of north
Ans: D
Chapter 2
Circle the correct answer
7. A car travels in a straight line covering a total distance of 90.0 miles in 60.0 minutes.
Which one of the following statements concerning this situation is necessarily true?
A) The velocity of the car is constant.
B) The acceleration of the car must be non-zero.
C) The first 45 miles must have been covered in 30.0 minutes.
D) The speed of the car must be 90.0 miles per hour throughout the entire trip.
E) The average velocity of the car is 90.0 miles per hour in the direction of motion.
Ans: E
8. Carl Lewis set a world record for the 100.0-m run with a time of 9.86 s. If, after reaching
the finish line, Mr. Lewis walked directly back to his starting point in 90.9 s, what is the
magnitude of his average velocity for the 200.0 m?
A) 0 m/s
B) 1.10 m/s
C) 1.98 m/s
D) 5.60 m/s
E) 10.1 m/s
Ans: A
9. A turtle takes 3.5 minutes to walk 18 m toward the south along a deserted highway. A
truck driver stops and picks up the turtle. The driver takes the turtle to a town 1.1 km to the
north with an average speed of 12 m/s. What is the magnitude of the average velocity of the
turtle for its entire journey?
A) 3.6 m/s
B)
C)
D)
E)
9.8 m/s
6.0 m/s
2.6 m/s
11 m/s
Ans: A
10. An elevator is moving upward with a speed of 11 m/s. Three seconds later, the elevator
is still moving upward, but its speed has been reduced to 5.0 m/s. What is the average
acceleration of the elevator during the 3.0 s interval?
A) 2.0 m/s2, upward
B) 2.0 m/s2, downward
C) 5.3 m/s2, upward
D) 5.3 m/s2, downward
E) 2.7 m/s2, downward
Ans: B
11. Starting from rest, a particle confined to move along a straight line is accelerated at a rate
of 5.0 m/s2. Which one of the following statements accurately describes the motion of this
particle?
A) The particle travels 5.0 m during each second.
B) The particle travels 5.0 m only during the first second.
C) The speed of the particle increases by 5.0 m/s during each second.
D) The acceleration of the particle increases by 5.0 m/s2 during each second.
E) The final speed of the particle will be proportional to the distance that the particle covers.
Ans: C
12. A car starts from rest and accelerates at a constant rate in a straight line. In the first
second the car moves a distance of 2.0 meters. How fast will the car be moving at the end of
the second second?
A) 4.0 m/s
B) 16 m/s
C) 2.0 m/s
D) 32 m/s
E) 8.0 m/s
Ans: E
Chapter 3
Circle the correct answer
13. A baseball is hit upward and travels along a parabolic arc before it strikes the
ground. Which one of the following statements is necessarily true?
A) The acceleration of the ball decreases as the ball moves upward.
B) The velocity of the ball is zero m/s when the ball is at the highest point in the arc.
C) The acceleration of the ball is zero m/s2 when the ball is at the highest point in the
arc.
D) The x-component of the velocity of the ball is the same throughout the ball's flight.
E) The velocity of the ball is a maximum when the ball is at the highest point in the arc.
Ans: D
A projectile is fired at an angle of 55.0o above the horizontal with an initial speed of
35.0 m/s.
This information is used for problems 14 and 15.
14. What is the magnitude of the horizontal component of the projectile's displacement
at the end of 2 s?
A) 30 m
B) 40 m
C) 10 m
D) 20 m
E) 50 m
Ans: B
15. How long does it take the projectile to reach the highest point in its trajectory?
A) 1.5 s
B) 2.4 s
C) 4.0 s
D) 6.2 s
E) 9.8 s
Ans: B
16. A spring-loaded gun is aimed horizontally and is used to launch identical balls with
different initial speeds. The gun is at a fixed position above the floor. The balls are fired
one at a time.
If the speed of the second ball fired is twice the speed of the first ball fired, how is the
horizontal range (denoted R in the figure) affected?
A) The range for both balls will be the same.
B) The range of the second ball will be half as much as that of the first ball.
C) The range of the second ball will be twice as large as that of the first ball.
D) The range of the second ball is about 1.4 times larger than that of the first ball.
E) The range of the second ball will be smaller than that of the first ball by a factor of
1.4.
Ans: C
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80m high cliff. The shell strikes the ground 1330 m from the base of the cliff. The drawing
is not to scale.
17. Determine the initial speed of the shell.
A) 4.0 m/s
B) 9.8 m/s
C) 82 m/s
D) 170 m/s
E) 330 m/s
Ans: E
Refer To: Ref 3-5
Difficulty: Hard
SectionDef: Section 3-2 and Section 3-3
18. What is the magnitude of the velocity of the shell as it hits the ground?
A) 4.0 m/s
B) 9.8 m/s
C) 82 m/s
D) 170 m/s
E) 330 m/s