The following forces start acting on a particle at rest at the origin of the coordinate system simultaneously: ${\vec F_1} = -4\hat i - 5\hat j + 5\hat k$,${\vec F_2} = 5\hat i + 8\hat j + 6\hat k$,${\vec F_3} = -3\hat i + 4\hat j - 7\hat k$,and ${\vec F_4} = 2\hat i - 3\hat j - 2\hat k$. The particle will move:

Three concurrent forces of the same magnitude are in equilibrium. What is the angle between the forces? Also,name the triangle formed by the forces as sides.

$A$ block of mass $8 \ kg$ is suspended by a rope of length $3 \ m$ from the ceiling. $A$ force of $40 \ N$ is applied horizontally to the block. Then the angle that the rope makes with the vertical in equilibrium is (acceleration due to gravity $= 10 \ m \ s^{-2}$,neglect the mass of the rope).

$A$ body under the action of several forces will have zero acceleration:

As shown in the figure,the two sides of a step ladder $BA$ and $CA$ are $1.6 \; m$ long and hinged at $A$. $A$ rope $DE$ of length $0.5 \; m$ is tied halfway up. $A$ weight of $40 \; kg$ is suspended from a point $F$,$1.2 \; m$ from $B$ along the ladder $BA$. Assuming the floor to be frictionless and neglecting the weight of the ladder,find the tension in the rope and the forces exerted by the floor on the ladder. (Take $g = 9.8 \; m/s^2$)

$A$ body is in equilibrium under the influence of a number of forces. Each force has a different line of action. The minimum number of forces required is: