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旧 2009-09-09, 05:33 PM   #1
huangyhg
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默认 how much load will swing

how much load will swing
load is hanged from a crane by a cable. crane suddenly stops, hence,
load and cable behave as pendulum. if i know length of cable and weight
of load, by what equation i can find how much further the load will swing?
i also know speed of crane
you need to use conservation of energy.
kineteic energy at crane stop = potential energy at top of swing. look up your physics texts for this type of situation.
csd
answer #2: if the crane operator is good, and here i mean more than competent, when the crane stops, the load will not
swing at all.
mike mccann
mccann engineering
csd72's approach will work it all cases of a sudden stop following a "steady state" horizontal movement.
if the weight's post-stop pendulum motion is going to be small enough, your problem can be treated as standard simple harmonic motion:
displacement = x = a*sin(wt)
and
velocity = x' = aw*cos(wt)
for a pendulum with small displacements, w = sqrt(g/l).
at the time the crane stops moving, t=0 and
x' = crane's previous travel velocity.
hence solve the velocity equation for "a", which is the answer you seek.
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