A.P. Physics (B) Practice Test
Name_________________________
Unit 3: Vectors and Projectile Motion
Part I
Directions: This part of the unit test is Multiple Choice. Indicate in some fashion (either by writing your
choice before the question number, or circling the letter choice) the letter of the choice that best answers the
question or statement. Each question is worth one point. You have fifteen minutes to complete this part of the
test. If you finish before the fifteen minute time limit, you may turn in this part of the exam and begin work on
part II. You may not use calculators or formula sheets on this part of the test. For any simple calculation, use
10.0 m/s2 for the acceleration due to gravity (g) when necessary. Neglect the effect of air friction unless
otherwise stated.
1.
Two vectors or equal magnitude are acting on an object at the same time. Vector A is acting to the west,
while vector B is acting to the south. What is the approximate direction of the resultant of these two
vectors?
A) Toward the south east.
B) Toward the north west.
C) Toward the south west
D) Toward the north east.
2.
At what angle between two vectors will their resultant have a minimum amount?
A) 90°
B) 180°
C) 0°
D) 45°
3.
A plane is flying through the air at 120 kph toward the north while a wind is blowing toward the east with a
speed of 50 kph. What is the magnitude of the actual velocity of the plane with respect to the ground?
A) 170 kph
B) 85 kph
C) 130 kph
D) 70 kph
4.
Two vectors each have magnitudes of 18 and 5. What is the minimum and maximum value the resultant of
these two vectors can have?
A) 5.5 and 11.5
B) 2.5 and 9
C) 3 and 13
D) 13 and 23
5.
At what angle between vectors does the square of the resultant’s magnitude equal the sum of the squares of
the magnitudes of each of the vectors?
A) 90°
B) 180°
C) 0°
D) 45°
Use the diagram to the right to answer question 6 – 9. It
represents a cart that is rolling along a tabletop at a constant
velocity and a ball that will drop at the instant the cart rolls off
the edge of the tabletop. The cart eventually lands at point Z.
X
6.
Compare the time it takes for the cart to travel from X to Z,
Y
as compared to the time it takes the ball to fall from X to Y.
A) The cart hits the ground before the ball.
B) The ball hits the ground before the cart.
C) They both hit the ground at the same time; the cart simply takes longer to get there.
D) They time to fall for both is the same.
7.
What happens to the velocity of the cart through its flight?
A) The horizontal component of the velocity remains constant while the vertical component increases as
gravity acts on the cart.
B) The horizontal and vertical components of the cart’s velocity increase with the action of gravity on the
cart.
C) The vertical component of the cart’s velocity remains constant while the horizontal component increases
as gravity acts on the cart.
D) The velocity of the cart remains constant through out its flight.
8.
If the cart’s velocity were doubled, what would happen to the time the cart falls as compared to the time the
ball falls?
A) The cart would land in half the time it takes the ball to fall.
B) The cart would land in twice the amount of time it takes the ball to fall.
C) The cart and ball will still land at the same time.
D) The cart will not land now, it is moving too fast.
9.
If the height of the table were tripled, what would happen to the flight of the ball?
A) The time of flight would be 3 times longer and the cart would land further from the table.
B) The time of flight would be three times longer but the cart would land the same distance from the table.
C) The time of flight would be nine times longer and the cart would land three times the original distance
from the table.
D) The time of flight would be unchanged, but the cart would land three times the original distance from
the table.
Z
10. When a ball is kicked at an angle to the horizontal, what component of the ball’s initial velocity determines
the amount of time the ball will spend in the air?
A) The horizontal component
B) The vertical component
C) There is no component of the velocity, but it is the angle that determines the time of flight.
D) None of these.
Use the diagram to the right to help you answer questions
11 – 15. It represents a ball that is kicked at a certain angle
with the horizontal.
Y
θ
11. Compare the time it takes the ball to move from X to Y as X
compared to the time it takes the ball to go from Y to Z.
A) The time to rise up to Y is less than the time to fall
down from Y.
B) The time to rise up to Y is greater than the time to fall down from Y.
C) The time to rise up to Y is equal to the time to fall down from Y.
D) The time to rise up to Y is unrelated to the time it takes to fall down from Y.
12. Which of the following best represents direction of the ball’s velocity at point Y?
A)
B)
C)
D)
13. What is the acceleration of the ball at point P?
A) g sin θ
B) g cos θ
C) g tan θ
D) g
14. At what angle of launch will the range the ball travels horizontally be at a maximum amount?
A) 30°
B) 60°
C) 0°
D) 45°
15. What is the same for the angles of launch of 15º and 75º?
A) The time of flight.
B) The maximum height the ball reaches
C) The horizontal velocity.
D) The horizontal distance traveled.
P
Z
16. As the angle of launch with the horizontal increases for a projected object (i.e. a golf ball being hit), what
happens to the horizontal component of the object’s velocity?
A) It increases.
B) It decreases.
C) It increases until it is a maximum at a 45° angle, then decreases again.
D) It is unaffected by the launch angle.
17. A carnival game involves trying to toss bean-bags through a ring that drops at the instant the bag is released
from the throwers hand. Where should the thrower aim to assure that her/his bean-bag will fly through the
center of the ring as it falls.
A) Directly at the center of the ring.
B) Above the ring to account for the pull of gravity on the bean-bag.
C) Below the ring to account for the downward motion of the ring.
D) Anywhere. At Carnivals and Fairs the games are rigged so that you automatically win no matter where
you throw.
18. A baseball is hit as a long fly ball to center right field. Compare the acceleration of the ball as it rises
through its arc, to the acceleration of the ball as it falls from the top of the arc to the outfielder’s glove.
A) The acceleration of the ball on the way up is greater than the acceleration coming back down.
B) The acceleration on the way up is half the acceleration on the way down.
C) The acceleration on the way up is the same in magnitude but opposite in direction to the acceleration of
the ball on the way down.
D) The acceleration of the ball throughout its flight is the acceleration due to gravity.
19. You are standing on the shore of a river and notice that the river is flowing west with a speed of 3.0 m/s.
You also notice that a boat on the river is sailing east at 8.0 m/s with respect to the shore. What is the
boat’s speed through the water?
A) 5.0 m/s
B) 11.0 m/s
C) 5.5 m/s
D) 24.0 m/s