Can Falling From a Chair and a Building Cause Different Levels of Injury?

In summary, the force that can hurt you when falling is due to deceleration, and the faster the initial velocity, the greater the deceleration and force. The stopping time is generally about the same in all cases. It is also important to consider kinetic energy, as the more energy you have upon impact, the more damage it can cause.
  • #1
Phys_Boi
49
0
If you fall off of a chair you don't get hurt, however, if you fall off of a building you die. How is this possible if you are experiencing the same force..
F=mg
 
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  • #2
As the old joke goes, it is not falling down that hurts, it when you stop falling!

The force that will hurt you is the one due to the deceleration, (negative acceleration) when you suddenly stop. The faster you were going, the greater the deceleration.
 
  • #3
DrClaude said:
As the old joke goes, it is not falling down that hurts, it when you stop falling!

The force that will hurt you is the one due to the deceleration, (negative acceleration) when you suddenly stop. The faster you were going, the greater the deceleration.
Okay! So how do you know the time from the initial velocity and 0 velocity?
 
  • #4
Phys_Boi said:
Okay! So how do you know the time from the initial velocity and 0 velocity?
There is no easy way to calculate that. It depends on so many things, like the softness of the ground and how much deformation you can sustain before breaking. But generally speaking, you can consider that the stopping time is about the same in all cases, and therefore that the higher the velocity, the stronger the force.

It is probably more relevant to consider it from the point of view of kinetic energy rather than force. The more kinetic energy you have, the more will have get dissipated quickly when you hit the ground, so the more of that energy will go into squashing you and breaking your bones.
 
  • #5
Okay! Thanks!
 

Related to Can Falling From a Chair and a Building Cause Different Levels of Injury?

1. What happens when an object hits the ground?

When an object hits the ground, it experiences a force called impact force. This force depends on the mass and velocity of the object, as well as the type of surface it hits. The impact force causes the object to deform and/or bounce back.

2. How does the height of an object affect the impact force when it hits the ground?

The height of an object affects the impact force in two ways: 1) a higher object will have a greater potential energy, resulting in a larger impact force when it hits the ground, and 2) a higher object will have a longer distance to decelerate, resulting in a longer impact duration and potentially a larger impact force.

3. Why do objects bounce when they hit the ground?

Objects bounce when they hit the ground because the impact force causes them to deform. As they deform, they store potential energy in the form of elastic potential energy. When the object regains its original shape, this energy is released, causing the object to bounce back.

4. What factors affect the impact force when an object hits the ground?

The impact force when an object hits the ground is affected by several factors, including the mass and velocity of the object, the height from which it falls, the type of surface it hits, and the shape and composition of the object.

5. Can an object hit the ground without experiencing any impact force?

No, an object cannot hit the ground without experiencing any impact force. Even if the object falls from a small height, it will still experience some impact force due to its mass and velocity. However, the impact force may be small enough to not cause any noticeable deformation or bouncing of the object.

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