Practice – 3-2 Vector Addition and Subtraction – Graphical Methods

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Practice - 3.2 Vector Addition and Subtraction: Graphical Methods

1. Find the following for path A in figure. All blocks are 120 m on a side

A. The total distance traveled.

B. The magnitude and direction of the displacement from start to finish.

2. Find the following for path B in figure.

A. The total distance traveled.

Figure for Problems 1, 2 and 3.

All blocks are 120 m on a side.

B. The magnitude and direction of the displacement from start to finish.

3. Find the following for path C in figure.

A. The total distance traveled

B. The magnitude and direction of the displacement from start to finish.

4. Suppose you walk 18.0 m straight west and then 25.0 m straight north. How far are you from your starting point, and what is the compass direction of a line connecting your starting point to your final position?

(If you represent the two legs of the walk as vector displacements A and B , as in the figure to the right, then this problem asks you to find their sum R = A + B .)

5. Parallelogram Method

To add A and B using the parallelogram method, place the tail of B so that it meets the tail of A. Take these two vectors to be the first two adjacent sides of a parallelogram, and draw in the remaining two sides. The vector sum (i.e. resultant), A + B, extends from the tails of

A and B across the diagonal to the opposite corner of the parallelogram. If the vectors are perpendicular and unequal in magnitude, the parallelogram will be a rectangle. If the vectors are perpendicular and equal in magnitude, the parallelogram will be a square.

A. Add these two vectors using your ruler, protractor and the parallelogram method on the axes below, and determine the resultant.

A

B

Vector

A

Magnitude Direction

B

Resultant

B. Add these two vectors using your ruler, protractor and the parallelogram method on the axes below, and determine the resultant.

A

B

Vector

A

B

Resultant

Magnitude Direction

C. Add these two vectors using your ruler, protractor and the parallelogram method on the axes below, and determine the resultant.

A

B

Vector

A

B

Resultant

Magnitude Direction

D. Add these two vectors using your ruler, protractor and the parallelogram method on the axes below, and determine the resultant.

A

B

Vector

A

B

Resultant

Magnitude Direction

6. Head-to-Tail Method

To add A and B using the head-to-tail method, place the tail of B so that it meets the head of A without changing the orientation/direction of either vector. To find the resultant, connect the tail of A to the head of B.

Example: A = 3.0 m/s @ 45 deg, B = 5.0 m/s @ 135 deg = 5.83 m/s, 104 deg

B

A

B R

A

Scale: 1 cm = 1 m/s

A. Add these two vectors using your ruler, protractor and the head-to-tail method on the axes below, and determine the resultant.

A:

B:

5.0 m/s @ 45 deg

2.0 m/s @ 180 deg

Magnitude Direction

Scale: 1 cm = 1 m/s

B. Add these two vectors using your ruler, protractor and the head-to-tail method on the axes below, and determine the resultant.

A: 6.0 m/s @ 225 deg

B: 2.0 m/s @ 90 deg

Vector

A

B

Resultant

Magnitude Direction

Scale: 1 cm = 1 m/s

C. Add these two vectors using your ruler, protractor and the head-to-tail method on the axes below, and determine the resultant.

A:

B:

5.0 m/s @ 45 deg

2.5 m/s @ 135 deg

Magnitude Direction

Scale: 1 cm = 1 m/s

D. Add these two vectors using your ruler, protractor and the head-to-tail method on the axes below, and determine the resultant.

A: 5.0 m/s @ 0 deg

B: 2.0 m/s @ 90 deg

Vector

A

B

Resultant

Magnitude Direction

Scale: 1 cm = 1 m/s

GRAND VECTOR CHALLENGE:

Add these three vectors using your ruler, protractor and the head-to-tail method on the axes below, and determine the resultant.

A: 2.0 m/s @ 315 deg

B: 5.0 m/s @ 180 deg

C: 2.0 m/s @ 60 deg

Vector

A

B

C

Magnitude Direction

Resultant

Scale: 1 cm = 1 m/s

Solutions:

1. A. 480 m

2. A. 1200 m

B. 379 m @ 71.6

o

B. 379 m @ 71.6

o

3. A. 1560 m B. 120 m @ 0 o

4. 30.8 m @ 125.8

o (NW)

5. A. 4.6 cm @ 27 o

C. 3.6 cm @ 79 o

C. 5.6 m/s @ 72

6. A. 3.9 m/s @ 67 o o

B. 2.1 cm @ 87 o

D. 2.6 cm @ -71 o

B. 4.8 m/s @ 208

D. 5.4 m/s @ 22 o

GRAND VECTOR CHALLENGE: 2.6 m/s @ 173 o o

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