A knot is kept at rest by three coplanar forces

PHYSICS · Subjective · CBSE · Physics · Motion in a Plane · Motion in a Plane

Problem

A knot is kept at rest by three coplanar forces. Force

F_1 = 80\,\text{N}

acts at an angle of

30^{\circ}

above the positive

x

-axis. Force

F_2 = 110\,\text{N}

acts along the negative

x

-axis. The third force

F_3

acts vertically downward and keeps the knot in equilibrium. (i) Calculate the angle

\beta

(measured above the negative

x

-axis) at which

F_2

must actually act so that equilibrium is maintained. (ii) Determine the magnitude of the downward force

F_3