Question
A uniform bar 25 meters long weighs 10,000 Newton's. From end A weight of 2500 Newton's is hung. At B the other end of the bar, there is a weight of 3500 Newton's. An upward force of 3000 Newton's is exerted 4 meters from B, while and upward force of 4000 Newton's is exerted 8 meters from A. Determine the magnitude, direction and point of application of the force needed to establish transitional and rotational equilibrium.
dont know where to even start. please help
dont know where to even start. please help
Answers
Damon
force, direction, distance from A
F , up (assumed) , x (unknown)
2500 , down , 0
4000, up , 8
10,000, down , 12.5
3000, up , 21
3500 , down , 25
sum of forces up = 0
so
-2500+4000-10000+F+3000-3500 = 0
F -5500 = 0
so
F = +5500 up
sum of clockwise moment = 0 about A
2500*0 -4000*6 +10000*12.5 -F*x-3000*21 + 3500*25 = 0
-24,000 +125,000 -F*x -63,000 +87,500=0
F * x = 125,500 but F = 5500
so
x = 22.8 meters from A
F , up (assumed) , x (unknown)
2500 , down , 0
4000, up , 8
10,000, down , 12.5
3000, up , 21
3500 , down , 25
sum of forces up = 0
so
-2500+4000-10000+F+3000-3500 = 0
F -5500 = 0
so
F = +5500 up
sum of clockwise moment = 0 about A
2500*0 -4000*6 +10000*12.5 -F*x-3000*21 + 3500*25 = 0
-24,000 +125,000 -F*x -63,000 +87,500=0
F * x = 125,500 but F = 5500
so
x = 22.8 meters from A
G
hmm the answer is 9000N upward 12 meters from B?