Forces 90N and 120N act in the directions 120° and 24...
Forces 90N and 120N act in the directions 120° and 240° respectively. Find the resultant of these forces.
−45(2i+√2j)
60(√3i+7j)
30(7i+√3j)
−15(7i+√3j)
Correct answer is D
F=Fcosθ+Fsinθ
\implies 90N = 90\cos 120° + 90\sin 120°
120N = 120 \cos 240° + 120 \sin 240°
R = F_{1} + F_{2}
= (90 \cos 120 + 120 \cos 240)i + (90\sin 120 + 120 \sin 240)j
= 90(-0.5) + 120(-0.5))i + (90(\frac{\sqrt{3}}{2}) + (120(-\frac{\sqrt{3}}{2}))j
= -105i - 15\sqrt{3}j = -15(7i + \sqrt{3}j)
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