A vector has an x-component of -309 m, and a y- component of 187m.

Find the magnitude of the vector [?] degrees

1 answer

To find the magnitude of the vector with components \[ x = -309 \, \text{m} \] and \[ y = 187 \, \text{m} \], we can use the Pythagorean theorem. The magnitude \( |\mathbf{v}| \) of the vector \(\mathbf{v}\) with components \( (x, y) \) is given by:

\[ |\mathbf{v}| = \sqrt{x^2 + y^2} \]

Substitute the given values:

\[ |\mathbf{v}| = \sqrt{(-309)^2 + 187^2} \]

Calculate the squares:

\[ (-309)^2 = 95581 \]
\[ 187^2 = 34969 \]

Sum the squares:

\[ 95581 + 34969 = 130550 \]

Take the square root of the sum:

\[ |\mathbf{v}| = \sqrt{130550} \approx 361.34 \, \text{m} \]

To find the direction (angle) \( \theta \) of the vector, we can use the inverse tangent function. The angle \(\theta\) (measured counterclockwise from the positive x-axis) is given by:

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

Substitute the given values:

\[ \theta = \tan^{-1}\left(\frac{187}{-309}\right) \]

\[ \theta = \tan^{-1}\left(-0.6052\right) \]

Calculate the angle using the arctangent function:

\[ \theta \approx -31.54^\circ \]

Since the vector is in the second quadrant (negative x and positive y components), we must add 180° to the angle to get the correct direction:

\[ \theta = -31.54^\circ + 180^\circ \]

\[ \theta \approx 148.46^\circ \]

Therefore, the magnitude of the vector is approximately \( 361.34 \, \text{m} \) and its direction is approximately \( 148.46^\circ \).