# 004 Components of a 3D force with given angles

**Problem 004**

Referring to Fig. 1.4, determine the angle between vector A and the y-axis.

A. 65.7°

B. 73.1°

C. 67.5°

D. 71.3°

**Solution 004**

$A_{xy} = A \sin 30^\circ$

$A_{xy} = 0.5A$

$A_y = A_{xy} \sin 40^\circ$

$A_y = (0.5A) \sin 40^\circ$

$A_y = 0.321A$

$\cos \theta_y = 0.321$

$\theta_y = 71.3^\circ$

Answer: **D**

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