Some Questions on Physics (Force) HELMETS

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Discussion Overview

The discussion revolves around the design and effectiveness of helmets, particularly focusing on the differences between soft and hard interiors, the criteria for helmet replacement, and the implications of helmet damage after collisions. The scope includes theoretical considerations, design principles, and safety standards related to helmet use.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that soft interiors reduce force during impacts by absorbing energy better than hard interiors, which transfer energy quickly and can lead to higher acceleration and potential injuries.
  • One participant notes that not all soft helmets are better, emphasizing the importance of certification and the actual energy absorption capabilities of the materials used.
  • Concerns are raised about the need to replace helmets after collisions, with a participant explaining that helmets are designed to absorb energy, and even minor damage can compromise their effectiveness.
  • Another participant suggests that helmets should be replaced every five years due to material degradation, which may lead to brittleness and reduced protective qualities over time.

Areas of Agreement / Disagreement

Participants express varying views on the effectiveness of helmet materials and the criteria for replacement. While there is some agreement on the need for replacement after collisions, the discussion remains unresolved regarding the specifics of material degradation and the implications for safety.

Contextual Notes

Participants mention the importance of certification for helmets and the variability in material performance, but do not provide specific data or studies to support their claims. The discussion lacks consensus on the exact mechanisms of energy absorption and the long-term effects of material aging.

Who May Find This Useful

This discussion may be useful for individuals interested in helmet safety standards, designers of protective gear, and those concerned with the physics of impact and injury prevention.

Shane-O
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1. Why is the force reduced for a helmet with a soft interior VS Hard interior?

2. What points would need to be considered during design and construction to ensure that the impact on the body is decreased? What criteria must be met?

3. Why should a helmet be replaced every 5 years regardless of wear and collision?

4. Once A helmet has been involved in a collision why should it be replaced?
 
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Shane-O said:
1. Why is the force reduced for a helmet with a soft interior VS Hard interior?

Hard interiors transfer the energy of the collision very quickly and efficiently. If you apply a force, such as the force of your head impacting the concrete, over a short amount of time or distance then the acceleration (or deceleration) is higher than if you increase the time or distance the force is transfered. One of the main causes of injuries is very high acceleration of the body. This causes internal organs to impact the inside of the body with a large amount of force, injuring them. Also, soft interiors absorb energy better than hard ones, leaving less energy available to cause injury.

Note that just because one helmet feels softer inside doesn't mean it is actually better. A soft foam that absorbs almost no energy will be much worse than a firmer one that absorbs a lot. Make sure any helmet you get is certified.

4. Once A helmet has been involved in a collision why should it be replaced?

Absolutely. Especially helmets like motorcycle helmets. They are designed so that on impact the helmet absorbs the energy, resulting in permanent damage to the helmet instead of your head. Even a small amount of damage to the helmet could be what causes permanent brain injury. Just because the helmet looks like it only has a few scratches doesn't mean the inside hasn't been damaged.
 
Last edited:
3. Why should a helmet be replaced every 5 years regardless of wear and collision?
Probably because the materials used degrade over time and their properties will not be the same...instead of remaining spongie, they dry and become brittle or something.
 
Thanks guys i really needed that
 

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