Question

The angle between two vectors of magnitudes 12 N and 3N on a body is 60${}^{∘}$ the resultant w .r.t. 12 N force is about

• A. 30${}^{∘}$
• B. 60${}^{∘}$
• C. 10${}^{∘}$
• D. 75${}^{∘}$

Answer 1

Answer: (C)

Using, tan $θ=\frac{F_{2}sinθ}{F_1+F_{2}cosθ}$ we get,
$tanÎ\pm =\frac{3sin60^{∘}}{12+3cos60^{∘}}$
$\frac{3×\sqrt{3/2}}{12+3×1/2}=\frac{3\sqrt{3}}{27}$
=$\frac{5.1962}{2}=0.19245$
$∴Î\pm =10.9^{∘}$