An 60 kg plank, 15 m long, hassupports at locations X1=4 m and X2=12m along the plank. Two additional forces F3=20N and F4=25 N act at thepoints X3=2 m and X4=10 m alongthe plank, making angles of 30 degrees and60 degrees with respect to the vertical.
a) from x-equilibrium, determine the value of F4,
b) from rotational equilibrium, determine the support forces N1and N2 acting at the location of the two supports, taking intoaccount the mass of the plank itself,
c) show that your answers are correct by demonstrating that theysatisfy equilibrium in y-.(i.e., that the sum of the forces in they-direction are zero, since the plank is stationary).