Theory question 107
StaticsForces F1 (10N, 090°), F2 (20N, 210°) and F3 (4N, 330°) act on a particle. Find, correct to one decimal place, the magnitude of the resultant force.
Show the model answer
Model answer
Components (east, north) = (F sin θ, F cos θ):
F₁ = (10, 0); F₂ = (−10, −17.32); F₃ = (−2, 3.46).
Resultant = (−2, −13.86); magnitude = √(4 + 192) = √196 = 14.0 N.
Explanation
Resolve each bearing into east and north parts, then add.