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Any help calculating work? I'm a little stumped.?

Any help calculating work? I'm a little stumped.? - Physics Forum

Any help calculating work? I'm a little stumped.? - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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Old 06-28-2009, 04:23 PM
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Default Any help calculating work? I'm a little stumped.?



A certain amount of work W is required to accelerate a motorcycle from rest to a speed v. How much work is required to accelerate the same motorcycle from rest up to a speed v/3?
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Old 06-29-2009, 07:51 PM
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Wink Re: Any help calculating work? I'm a little stumped.?

If my high school physics is correct, then:

F = m x a
W = Fxd
a = v/t = dd/dt / t

W = mad=md(v/t)
W'= md(v/3) /t = mdv/3t

difference of W-W' = 1mdv/t - 1/3 (mdv/t) =2/3 mdv/t
so it takes one third the work "W" to accelerate to 1/3 speed "v"

Last edited by danfive; 06-29-2009 at 07:55 PM.
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