Chapter 3: Vectors in Physics
Practice Questions




1.  

If you drive west at 20 km/h for one hour, then drive east at 15 km/h for one hour, your net displacement will be

5 km east.
35 km west.
35 km east.
5 km west.


2.  

A 200-lb force is pulling on an object, as shown. The sign of the x and y components of the force are

x (positive), y (positive).
x (positive), y (negative).
x (negative), y (positive).
x (negative), y (negative).


3.  

Three boys each pull with a 20-N force on the same object. The resultant force will be

zero.
20 N to the left.
20 N up.
20 N down.


4.  

Consider a plane flying with groundspeed Vg and airspeed Va in a wind with speed V. Which of the following relationships is true?

Vg will always equal Va + V
Vg can be greater than Va + V
Vg can be less than Va - V
Vg can have any value between Va + V and Va - V


5.  

Two vectors, R and S, are known:

If vector S is subtracted from vector R, the vector T = R - S is



6.  

Two vectors, R and S, are known:

If vector R is subtracted from vector S, the vector T = S - R is



7.  

Two vectors, R and S, are known:

If vector S is added to the vector R, then the vector T = R + S is



8.  

If the acceleration vector of a body is perpendicular to the velocity vector, which of the following must be true?

The speed is changing.
The direction is changing.
Both the speed and the direction are changing.
The direction is not changing.


9.  

A vector of magnitude 10 has an angle with the positive x-axis (East) of 120 degrees. What are its components?

5 and 8.7
-5 and 8.7
5 and -8.7
-5 and -8.7


10.  

A vector of magnitude 10 has an angle with the positive x-axis (East) of -60 degrees. What are its components?

5 and 8.7
-5 and 8.7
5 and -8.7
-5 and -8.7


11.  

A vector has components x=6 m and y=8 m. What is its magnitude and direction?

10 m and 30 degrees
14 m and 37 degrees
10 m and 53 degrees
14 m and 53 degrees


12.  

A vector has components x= -2 m and y=-2 m. What is its direction (angle with respect to East)?

45 degrees
135 degrees
225 degrees
-45 degrees


13.  

Three vectors have components (x,y):A=(2,3),B=(4,-7) and C=(-6,-3). What is the magnitude of the resultant vector (D=A+B+C)?

-7
17.7
15
7


14.  

Three vectors have components (x,y):A=(2,3),B=(4,-7) and C=(-6,-3). What is the magnitude of the resultant vector (D=A-B-C)?

13.6
15
52
7


15.  


Where in the above figure is the velocity positive?

A
B
C
D
E
F


16.  

At which point in the figure in question 15 is the velocity and acceleration zero?

A
B
C
D
E
F


17.  

At which point in the figure in question 15 is the velocity zero and the acceleration positive?

A
B
C
D
E
F


18.  

At which point in the figure in question 15 is the speed the greatest?

A
B
C
D
E
F


19.  

At which point in the figure in question 15 is the velocity zero and acceleration negative?

A
B
C
D
E
F


20.  

At which points in the figure in question 15 is the velocity and acceleration zero?

B, E and F
A and C
C and D


21.  

At which point in the figure in question 15 is the acceleration zero?

B, E and F
A and C
C and D


22.  

If the sum of two vectors equals zero, the magnitude of their difference is

equal to the magnitude of either one.
equal to twice the magnitude of either one.
less than twice the magnitude of either one.


23.  

A sailboat travelling with a speed of 4 knots through the water heads directly up river against a 3 knot current. Its speed over ground is

1 knot.
7 knots.
3 knots.
5 knots.


24.  

A sailboat travelling with a speed of 4 knots through the water heads heads directly down river with a 3 knot current. Its speed over ground is

1 knot.
3 knots.
5 knots.
7 knots.


25.  

A sailboat travelling with a speed of 4 knots through the water heads heads directly across a river which has a 3 knot current. Its speed over ground is

1 knot.
3 knots.
5 knots.
7 knots.


Practice Questions: Practice Questions by Carl Adler, East Carolina University. ©2002 by Prentice Hall, Inc.


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