- #1
yaro99
- 75
- 0
Homework Statement
Homework Equations
ƩFx=0
ƩFy=0
ƩM=0
The Attempt at a Solution
I will call the tire forces A (for the trailer), and B and C (for the truck)
I got the correct answer for A by isolating the trailer and writing this equation for it:
ƩMD = 2400*9 - 2*A*11 = 0
A = 982lb ↑
to find D, I wrote this equation, still just for the trailer:
ƩFy = 2*A - 2400 + D = 0
2*982 - 2400 + D = 0
D = 436lb ↑
I got the wrong answers for B and C.
To find them, I tried isolating the truck and using these equations:
ƩMC = 2900*4 - 2*B*9 - D*12 = 0
2900*4 - 436*12 - 18*B = 0
B = 354 lb ↑
ƩFy = D + 2*B - 2900 +2*C = 0
436 + 2*354 - 2900 + 2*C = 0
C = 878lb ↑
Also, I inadvertently found the answer to part (b) when I started the problem by calculating the equilibrium equations for the truck that I wrote above, but forgetting to factor the truck's weight into the equations. I'm not sure why this would yield the correct answer; I would appreciate it if someone could try to explain that.