Lamp tips over and hits the top of the head

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    Head Lamp Tips
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Discussion Overview

The discussion revolves around estimating the g-force experienced when a lamp tips over and strikes a person's head. Participants explore the factors influencing the impact, including the weight of the lamp, the distance it falls, and the material properties of both the lamp and the head.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant states the need to calculate the g-force based on the weight of the lamp (300 grams) and the distance it falls (15 centimeters) before hitting the head.
  • Another participant emphasizes the importance of deformation during impact, suggesting that no deformation would lead to infinite acceleration, which is not realistic.
  • A participant reiterates the need to know the speed of the lamp just before impact and the time taken to stop to calculate the g-force accurately.
  • One participant proposes using a braking distance of 1 millimeter for both the scalp and the lamp, alongside a falling acceleration of 10 m/s².
  • Another participant clarifies that while the lamp is not in free fall, assuming free fall can provide a reasonable estimate for speed, and mentions a formula for calculating speed after falling a certain height.
  • One participant suggests estimating the deceleration experienced by the lamp in terms of g-force, while questioning the relevance of the head's condition in the calculations.

Areas of Agreement / Disagreement

Participants express differing views on the assumptions necessary for calculating the g-force, particularly regarding deformation and the nature of the fall. No consensus is reached on the exact method or values to use for the calculations.

Contextual Notes

Participants note the complexity of estimating stopping time and deceleration, indicating that precise calculations may require more detailed information about the lamp's mass distribution and material properties.

Who May Find This Useful

This discussion may be of interest to those studying impact physics, material properties, or anyone curious about the dynamics of falling objects and their effects on human anatomy.

freexd
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Imagine a lamp tips over and hitst the top of the head. the lamp weighs about 300 gram and the distance when it started to tip over and hit the head was about 15 centimeters. in the moment of the impact the lamp has tipped over excactly for 90 degrees. The material is Metal that deforms only very little.

what g force did the impact have?
 
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It depends crucially on the deformation of the metal and the floor. Absolutely no deformation would lead to "infinite" acceleration, but absolutely no deformation is impossible.
As rough approximation: (braking distance)/(distance it fell).
 
freexd said:
Imagine a lamp tips over and hitst the top of the head. the lamp weighs about 300 gram and the distance when it started to tip over and hit the head was about 15 centimeters. in the moment of the impact the lamp has tipped over excactly for 90 degrees. The material is Metal that deforms only very little.

what g force did the impact have?
You need to know how fast it was going right before the impact, and how long it took to stop.
 
As braking distance I would take 1 millimeter for the deformation of the scalp and 1 millimeter for the deformation of the lamp.

as falling acceleration we could take 10 m/s (falling acceleration)

the time it took to stop is hard to estimate
 
10m/s is a speed, the gravitational acceleration in free fall is 10m/s2.
The lamp is not in free fall, however, as its base always has contact to the floor. It is possible to get a good estimate of its speed (if you know its mass distribution and so on), but I don't think you care about a factor of ~1.5 here, so assuming a free fall gives a reasonable estimate. There is a simple formula to find the speed of an object after falling down a given height. This will also help to find the stopping time.
Alternatively, you can directly use the approximation I gave in post 2. It assumes uniform deceleration which is probably not true either, but precise values are much more work.
 
You can estimate the deceleration that the lamp will experience and express that in terms of g, but perhaps you care more about the head?
 
CWatters said:
but perhaps you care more about the head?
Somebody else's!.
 

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