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4 votes

Is a single large impact better than several small impacts for breaking ice

Multiple smaller, light impacts are better. The heavy concentrated impact can damage and crack the already fragile pavement which has likely lost most of its resilience due to the freezing ...
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4 votes

How effective are screen protectors?

I don't think of a screen protector as a mono layer, but a lamination. Deformable (softer) materials (possibly above and also) below the rigid layer (this layer also generally provides adhesion). That ...
  • 486
2 votes
Accepted

Can someone please explain how impact is absorbed?

During impact what usually happens is that a moving object with mass $m$ with an initial velocity $v_0$ stops (or rebounces) in a very short time $\Delta t$. Assuming a body stops during impact this ...
  • 22.9k
2 votes
Accepted

Testing specimens by dropping a ball on them and counting the number of drops required before the collapse. A better way?

It sounds like you could modify the procedure and equipment used for a soil standard penetration test (ASTM D1586). In this test, a hammer of specific weight is dropped a specific distant to strike ...
  • 10.7k
1 vote
Accepted

How does an impact driver convert the lateral motion of the spring expansion, into rotational force?

https://www.wonkeedonkeetools.co.uk/cordless-impact-drivers/how-does-the-impact-function-work Coil springs can be both compressed and twisted. The compression of the spring is what allows the hammer ...
  • 3,520
1 vote

Vibration following an impact

Regarding your first question IMHO eigenvalue analysis is appropriate and valid as long as the material is within the elastic range. Also another misconception is that, the application of eigenvalue ...
  • 22.9k
1 vote
Accepted

Why do some metals with bcc structure show ductile-brittle transition in charpy impact test?

It essentially depends on the fracture mechanisms available to the material at the temperature in question. In general, dislocations are more mobile at higher temperatures, enabling plastic ...
  • 36
1 vote

How to create a mechanical equivalent to dropping object onto steel floor

Freefall friction-less velocity of an object falling 1 meter is $$ V= \sqrt{2hg}= \sqrt{2g}=4.427m/s $$ This velocity decreases to zero in a short time after the crash, and unless your ball is not a ...
  • 21.2k
1 vote
Accepted

Does the surface roughness play any role in shock absorbing?

No, look at it this way: you are removing material that would otherwise help break the fall. All it does is give the mass a chance to penetrate deeper into the drop pad. It would be ok if you add ...
  • 21.2k

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