Theory question 105
StaticsThree forces 10 N, 14 N and 16 N acting on a particle keep it in equilibrium. Find the angle between the forces 10 N and 16 N.
Show the model answer
Model answer
The 14 N force balances the resultant of the 10 N and 16 N forces.
14² = 10² + 16² + 2(10)(16) cos θ, so 196 = 356 + 320 cos θ and cos θ = −½.
θ = 120°.
Explanation
The resultant of two forces equals the third force reversed.