How to Calculate Impact Height for 40 g's Acceleration

  • Context: Undergrad 
  • Thread starter Thread starter tmifsu530
  • Start date Start date
  • Tags Tags
    Force Height
Click For Summary

Discussion Overview

The discussion revolves around calculating the height from which an object must be dropped to achieve a specified acceleration of 40 g's upon impact with the Earth. The scope includes conceptual understanding of acceleration during impact and the conditions of the collision.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks to determine the height necessary for an object to impact the Earth at an acceleration of 40 g's.
  • Another participant questions the meaning of "impacting at a certain acceleration," suggesting that acceleration is not the same as velocity.
  • A clarification is provided that the desired acceleration refers to the acceleration experienced upon hitting the ground, assuming a perfectly inelastic collision.
  • One participant asserts that it does not matter from which height an object is dropped, as it will never experience greater than 1 g acceleration upon impact.
  • A later reply suggests that a perfectly inelastic collision could lead to infinite acceleration, raising further questions about the scenario.
  • Another participant introduces the idea that the impact acceleration may depend on the object's properties and the surface it impacts, providing examples of different scenarios with varying results.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of achieving 40 g's acceleration upon impact, with some asserting it is impossible while others suggest it may depend on specific conditions.

Contextual Notes

There are unresolved assumptions regarding the nature of the collision and the definitions of acceleration in this context. The discussion does not reach a consensus on the calculations or the physical principles involved.

tmifsu530
Messages
3
Reaction score
0
Hi everyone,

This may seem like a simple problem but it seems to be escaping me.

Say I have an object of a given mass, m, and I want it to impact the Earth at an acceleration of 40 g's. What height, h, must I drop the object at?

Again, I feel like I'm just missing a step so please let me know how you got there if you can find the answer.

Thanks!
 
Physics news on Phys.org
Um? You haven't explained what "impacting at a certain acceleration" means. Do you mean at a speed? g is a unit of acceleration, not velocity.
 
I'm sorry. I want the acceleration that it experiences once it hits the ground to be 40 g's, assuming perfectly inelastic collision with the Earth.
 
It does not matter from which height you drop something, it will never experience greater then 1g acceleration.
 
Nevermind, as I attempted to rephrase the question as I believe I wasn't being clear I worked it out myself! Ha thanks for the help anyway!
 
tmifsu530 said:
I'm sorry. I want the acceleration that it experiences once it hits the ground to be 40 g's, assuming perfectly inelastic collision with the Earth.

Perfectly inelastic? I imagine it would experience infinite acceleration.
 
tmifsu530 said:
Hi everyone,

Say I have an object of a given mass, m, and I want it to impact the Earth at an acceleration of 40 g's. What height, h, must I drop the object at?

Thanks!

If you are talking about Shock and Vibration measurement, that will depend on the object itself and the properties of the surface that the object falls on.

For instance if you dropped a hard drive from feet feet onto a very plush carpet, you might get 40gs (2ms half-sine). But pull the carpet back and let the drive fall onto bare concrete floor and you'll get over 1,000gs (0.5ms 1/2 sine-wave).
 

Similar threads

Replies
4
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 19 ·
Replies
19
Views
7K
  • · Replies 27 ·
Replies
27
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K