Question

When forces F₁, F₂, F₃ are acting on a particle of mass m such that F₂ and F₃ are mutually perpendicular, then the particle remains stationary. If the force F₁ is now removed, then the acceleration of the particle is

(a) F₁/m

(b) F₂ F₃/mF₁

(c) (F₂ - F₃)/m

(d) F₂/m

Answer 1

Correct option (a) F₁/m
Explanation:
The particle remains stationary under the acting of three forces F_1, F₂  and F_3, it means resultant force
is zero,

F_{1 +}  F_{2  +}  F3 = 0

Since, in second cases F₁ is removed (in terms of magnitude we are talking now), the forces acting are F₂ and F₃ the resultant of which has the magnitude as F_1, so acceleration of particle is F_1/m in the direction opposite to that of F_1.