Use the exact values you enter in previous answer(s) to make later calculation(s

Question

Use the exact values you enter in previous answer(s) to make later calculation(s).

A uniform wooden plank of mass 14 kg rests on two supports as shown in the figure below. The plank is at rest, so it is in translational equilibrium and rotational equilibrium. (Let L1 = 1.5 m, L2 = 6.8 m, and L3 = 3.1 m.)

(a) Make a sketch showing all the forces on the plank. Be sure to show where the forces act.

(b) Choose the left-hand support for the pivot point and calculate the magnitude of torque from each of the forces in part (a).

(c) Express the conditions for translational and rotational equilibrium. (Use the following as necessary: FR for the force supplied by the right support, FP for the force supplied by the plank, FL for the force supplied by the left support, ?R for the torque due to the right support, ?P for the torque due to the plank, and ?L for the torque due to the left support. Indicate the direction with the sign of your answer.)

(d) Solve to find the magnitudes of the forces exerted by the two supports on the plank.

Explanation / Answer

Fr + Fl =14*9.8=137.2 N

moment about left support

14*9.8*6.2=Fr*6.8

Fr=125.0941176470588
so
Fl = 12.11

torque due to Fl about left support=0
torque due to Fr about left support=850.64 anti clock wise
torque due to mg about left support= 850.64 clock wise

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