Find work done given time, acceleration, and mass

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To find the net work done on a box with a mass of 6.0 kg accelerated at 2.2 m/s² for 5.9 seconds, the force can be calculated using F=ma, resulting in 13.2 N. The work done is expressed as W=Fd*cos(0), but the distance (d) needs to be determined first. The discussion suggests using kinematic equations to find distance, with one approach being to calculate final velocity (vf) using v=vi+at. However, there is confusion regarding the calculations, as the derived distance appears inconsistent with expected values, indicating a potential error in the application of the equations. Clarifying the relationship between speed and distance is essential for accurate work calculation.
daltomagne
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a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of
2.2 m/s^2 for 5.9 s. Find the net work done on the box

m=6.0kg
a=2.2m/s^2
t=5.9 s
a=0 degrees

i know W=Fdcos(a)
and F=ma


so,
F=6.0kg*2.2m/s^2=13.2N
W=13.2N*d*cos0=13.2N*d

I am a little unsure as how to find d though. would it be one of the kinematic equations?
 
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hi daltomagne! :smile:

(try using the X2 icon just above the Reply box :wink:)
daltomagne said:
a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of
2.2 m/s^2 for 5.9 s. Find the net work done on the box

I am a little unsure as how to find d though. would it be one of the kinematic equations?

That's right. :smile:

You can either use one of the standard constant acceleration equations to find d, or you can use another of them to find vf, and then apply the work-energy theorem ( work done = change in mechanical energy).
 
so I'm thinking v=vi+at and that gives me vi=-12.98m/s
and
xf=xi+vit+1/2at2?
but that gives me a value for x=-38.3 m?

so something isn't adding up
 
where's the contradiction? :confused:

one figure is speed, the other is distance, they should both give you the same work. :wink:
 
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