In: Physics
An 60 kg plank, 15 m long, has supports at locations X1=4 m and X2=12 m along the plank. Two additional forces F3=20 N and F4=25 N act at the points X3=2 m and X4=10 m along the plank, making angles of 30 degrees and 60 degrees with respect to the vertical.
a) from x-equilibrium, determine the value of F4,
b) from rotational equilibrium, determine the support forces N1 and N2 acting at the location of the two supports, taking into account the mass of the plank itself,
c) show that your answers are correct by demonstrating that they satisfy equilibrium in y-.(i.e., that the sum of the forces in the y-direction are zero, since the plank is stationary).