Hi, I was wondering if I could have a bit of guidance with this question (if you can understand my drawing of it!)(adsbygoogle = window.adsbygoogle || []).push({});

http://img222.imageshack.us/img222/376/scan1md.jpg" [Broken]

It is basically a representation of the main hydraulic ram and boom assembly for a telescopic handler, similar to this:

http://www.jcb-store.com/BidZone/newImages/HPIM0365(1).JPG" [Broken]

Theta = angle of boom from the vertical

Phi = angle of cylinder from the horizontal

F = Force from the cylinder piston

m1g = Mass of the boom x gravitational constant

m2g = Mass of load x gravitational constant

b = Total length of boom

c = Length of cylinder

L = Extension of piston from cylinder

d = distance from boom pivot to boom/cylinder connection pivot

The magnitudes of F, m1g, m2g, b, c, d are all constant

Theta, Phi, and L can all vary

When time, t = 0, L=0, theta dot=0, phi dot=0

Basically I need to calculate the values of theta and L at time t.

My working so far (probably gone completely down the wrong path!):

Taking moments about A (the boom pivot point)

(d x F x sin phi) - (1/2b x m1g x sin theta) + (b x m2g x sin theta) = (d x (m1+m2) x "theta double dot")

That's about as far as I can get, and I'm not even sure if that's correct. If anyone can even give me a hint as to how to start this question, that'd be a great help. If any more information/a better diagram is needed, just ask.

Thanks a lot for your help, your all absolute stars

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# Homework Help: Mechanics Question

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