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A ship is sailing 7 miles per hour with a direction angle of 25 degrees. On deck, the captain fires a cannonball that flies 100 miles per hour with a direction angle of 280 degrees.What is the direction angle of the cannonballs resultant vector?

User Bob Kuhar
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1 Answer

17 votes
17 votes

ANSWER:

283.9°

Explanation:

We must calculate the components of each vector, add the corresponding components to obtain the components of the resulting vector, like this:


\begin{gathered} V_1=7\text{ mph, 25}\degree\rightarrow \\ \\ V_2=100\text{ mph, 280}\degree\text{ or 10\degree \lparen280\degree - 270\degree\rparen} \\ \\ \text{ x-axis components} \\ \\ V_(1x)=7\cdot\cos25\degree=6.34 \\ \\ V_2x=100\cdot\sin10\degree=17.36 \\ \\ \text{y-axis components} \\ \\ V_(1y)=7\cdot\sin25\degree=2.96 \\ \\ V_(2y)=100\cdot\cos10\degree=98.48 \\ \\ \text{ We calculate the components of the resulting vector taking into account the quadrant of the vectors \lparen for the signs\rparen:} \\ \\ V_x=6.34+17.36=23.7 \\ \\ V_y=2.96-98.48=-95.52 \end{gathered}

Knowing the components of the resulting vector, calculate the angle, as follows:


\begin{gathered} \tan\theta=(y)/(x) \\ \\ \tan\theta=(-95.52)/(23.7) \\ \\ \theta=\:\tan^(-1)\left((-95.52)/(23.7)\right) \\ \\ \theta=-76.06541\degree \\ \\ \text{ In the Cartesian plane at an angle it will be:} \\ \\ \theta=360\degree-76.06541\degree=283.93459\degree \\ \\ \theta=283.9\degree \end{gathered}

The angle of the resulting vector is 283.9°

User Kturney
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