7. Given the vectors A = 4 m east and B = 3 m south, using graphical addition determine which of the following most likely represent the magnitude and direction of the sum vector (A + B) respectively. (You should be able to answer it with sketches not drawn to scale.) (1 point)A. 5 m, 323.13 degB. 7 m, 323.13 degC. 5 m, 216.87 degD. 5 m, 36.87 degE. 7 m, 216.87 deg

7 Given the vectors A 4 m east and B 3 m south using graphical addition determine which of the following most likely represent the magnitude and direction of th class=

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ANSWER

[tex]A.\text{ }5\text{ m, }323.13\text{ deg}[/tex]

EXPLANATION

First, let us make a sketch of the vectors:

The thick black line represents the vector sum of the two vectors A and B.

We see that the coordinates of the vector (A + B) are:

[tex](A+B)=(4,-3)[/tex]

We can write it in component form as:

[tex]A+B=4i-3j[/tex]

To find the magnitude of (A + B), we have to find the length of the line using the formula:

[tex]L=|A+B|=\sqrt{x^2+y^2}[/tex]

where (x, y) are the coordinates of the vector.

Hence, the magnitude of the vector is:

[tex]\begin{gathered} |A+B|=\sqrt{(4)^2+(-3)^2}=\sqrt{16+9} \\ \\ |A+B|=\sqrt{25} \\ \\ |A+B|=5\text{ m} \end{gathered}[/tex]

To find the direction of the vector (A + B), we have to apply the formula:

[tex]\theta=\tan^{-1}(\frac{y}{x})[/tex]

Therefore, the direction of the vector is:

[tex]\begin{gathered} \theta=\tan^{-1}(-\frac{3}{4}) \\ \\ \theta=143.13\text{ deg or }323.13\text{ deg} \end{gathered}[/tex]

Since the vector is in the fourth quadrant, then, the direction is:

[tex]\theta=323.13\text{ deg}[/tex]

Therefore, the magnitude and direction of the sum vector (A + B) are:

[tex]A.\text{ }5\text{ m, }323.13\text{ deg}[/tex]

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