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(6%) Problem! 6: Consider a bar, of length 5.5 m, shown in the figure, being act

ID: 1775372 • Letter: #

Question

(6%) Problem! 6: Consider a bar, of length 5.5 m, shown in the figure, being acted on by three forces. The magnitudes of the first two forces are 21 N and 31 N, and the first force is acting on the end of the bar at an angle of 31 as shown. F3 Fi F2 33% Part (a) What is the torque, in newton-meters, due to F1 on this bar relative to the left end? Use a coordinate system with positive directed out of the screen. 33% Part (b) what is the torque, in newton-meters, due to F2 on this bar relative to the left end, if this force is acting at the midpoint of the bar? Use a coordinate system with positive directed out of the screen 33% Part (c) what is the magnitude of the force F3, in newtons, if the force is a distance 0.15 m from the left end and the bar is not rotating? Grade Summary Deductions 0%

Explanation / Answer

a) T1 = r*F1*sin(phi) = 5.5*21*sin(31) = 59.5 N-m


b) T2 = (r/2)*F2*sin(90) = (5.5/2)*31*sin(90) = 85.25 N-m

c) Torque due to all forces is zero


T1+T2 = T3

59.5+85.25 = (F3*d)

144.75 = (F3*0.15)

F3 = 965 N