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Re: [Phys-L] real-world physics



If the bubble wrap acts like an ideal spring, completely reversing the motion does imply that a lower limit on the maximum acceleration of 2g.

In this case, it's simpler to consider the duration of the collision. Starting at a speed of 120 mph (50 m/s) and changing that to zero implies an average speed during collision of 25 m/s. Traveling a distance of 4 inches (0.1 m) at this speed means that the collision takes 0.004 seconds. Knowing our delta-v and delta-t we can say that the average acceleration during that time is 12,500 m/s/s (1250 g).

That is the calculation that the Mythbusters should have done before attempting to build this.

Paul


On Jun 6, 2012, at 5:46 PM, brian whatcott wrote:

Hmmm.. with a compressing spring, an increasing force, providing an increasing retardation.
So certainly not constant acceleration. I think I was responding to the idea of doubling the acceleration by the reversed direction, which seems also mistaken

Brian W


On 6/6/2012 11:54 AM, brian whatcott wrote:
Comparable speed at reciprocal heading, with constant acceleration possibly??

Brian W

On 6/6/2012 10:57 AM, Bernard Cleyet wrote:
On 2012, Jun 06, , at 08:19, John Clement wrote:

I wonder if the boxes were filled with bubble wrap.
A possible worsening, as if not popped, bouncing, doubling the acceleration.




Since these are
professionals I suspect they first tried a dummy and that they know how to
calculate forces.

So testing an idea is not all that farfetched.
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