Question

Three forces start acting simultaneously on a particle moving with velocity vector v. These forces are represented in magnitude and direction by the three sides of a triangle ABC (as shown). The particle will now move with velocity

(a) less than vector v
(b) greater than vector v
(c) | vector v | in the direction of the largest force BC
(d) vector v , remaining unchanged

Answer 1

(d) : By triangle of forces, the particle will be in equilibrium under the three forces. Obviously, the resultant force on the particle will be zero. Consequently, the acceleration will be zero. 

Hence the particle velocity remains unchanged at vector v.