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A body is acted upon by forces F_{1} = (10 N, 090°) ...

A body is acted upon by forces F_{1} = (10 N, 090°) and F_{2} = (6 N, 180°). Find the magnitude of the resultant force.

A.

11.6 N

B.

11.7 N

C.

11.8 N

D.

11.9 N

Correct answer is B

F = F \cos \theta i + F \sin \theta j (Resolving F into its components)

F_{1} = (10 N, 090°) = 10 \cos 90 i + 10 \sin 90 j

= 10 j

F_{2} = (6 N, 180°) = 6 \cos 180 i + 6 \sin 180 j

= -6 i

R = - 6 i + 10 j

|R| = \sqrt{(-6)^{2} + (10)^{2}}

= \sqrt{136}

= 11.7 N