- #1
Reisen
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Your standard first-post-pleading-for-help here :)
This doesn't make sense:
Say you've got a setup like in picture 1 (floor is frictionless)
If the F readout on the scale is 18N, and the box is 5kg and F=ma, then 18N/5kg = 3.6m/s^2 = a, right? Okay...
Now, if the velocity is constant, there is no acceleration, yes? But then F = ma, then F = 5kg * (0m/s^2) = 0. But if the boxcar were moving forward at a constant rate with a frictionless floor, the box would slide to the back, wouldn't it? The rope has to be exerting SOME force on the box to keep it in place, so that's why I'm wondering how this doesn't work.
Thanks in advance to whoever points out my mistake :)
-Reisen
This doesn't make sense:
Say you've got a setup like in picture 1 (floor is frictionless)
If the F readout on the scale is 18N, and the box is 5kg and F=ma, then 18N/5kg = 3.6m/s^2 = a, right? Okay...
Now, if the velocity is constant, there is no acceleration, yes? But then F = ma, then F = 5kg * (0m/s^2) = 0. But if the boxcar were moving forward at a constant rate with a frictionless floor, the box would slide to the back, wouldn't it? The rope has to be exerting SOME force on the box to keep it in place, so that's why I'm wondering how this doesn't work.
Thanks in advance to whoever points out my mistake :)
-Reisen
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