Suppose you first walk 12.0 m in a direction 200 west of north and then 20.0 m in a direction 40.00 south of west. 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?

Respuesta :

Complete Question

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Answer:

the compass direction of the resultant displacement is  [tex]\theta  =4.7^o [/tex] south of west

Explanation:

Generally using cosine we can obtain the resultant R as follows

     [tex]R^2  =  A^2  + B^2 -2ABcos(70)[/tex]

=>   [tex]R  =  \sqrt{12^2  + 20^2  - 2(12 ) *  (20) cos  70}[/tex]

=>    [tex]R  =  19.48 \  m[/tex]

We can obtain the direction of the resultant by first  using sine rule to obtain angle C as follows

       [tex]\frac{A}{sin  C}  =  \frac{R}{sin70 }[/tex]

=>    [tex]C=  sin ^{-1} [\frac{A *  (sin 70)}{R} ][/tex]

=>    [tex]C =  sin ^{-1} [\frac{20 *  (sin 70)}{19.48} ][/tex]

=>  [tex]C =  74.7 ^o[/tex]

Then the direction is obtained as

       [tex]\theta  =  C  -  70[/tex]

=>    [tex]\theta  = 74.7   -  70[/tex]

=>     [tex]\theta  =4.7^o [/tex]

Hence the compass direction of the resultant displacement is  [tex]\theta  =4.7^o [/tex] south of west

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