Theory question 108
StaticsFind the direction of the resultant of the forces in the diagram.
Show the model answer
Model answer
Components (x, y): 10 N at 30° to the y-axis: (−5, 8.660); 8√2 N at 45°: (8, 8); 20 N at 60° below the negative x-axis: (−10, −17.321).
Resultant = (−7, −0.660).
It points 5.39° below the negative x-axis (tan⁻¹(0.660/7)): direction 185.4° from the positive x-axis, i.e. bearing 264.6°.
Explanation
Resolve every force into x and y components first.