Question:

Can I use F=ma when I stub my toe?

by  |  earlier

0 LIKES UnLike

Yesterday I had a very common accident - I managed to walk into the corner of a heavy object, smashing my little toe into it at fairly high speed, and still managed NOT to break the toe. I'll spare the gorey details but needless to say there was quite a lot of blood and it's going to be quite sore and a minor inconvenience (today I can only wear flip-flops as they don't put any pressure on that part of my foot) for a few days.

Then it got me wondering, what would the force of such an impact be on that part of the foot which absorbed the impact? Can I apply F=ma? Has anyone every bothered to quantify examples - we know that designers and engineers make these calculations on physical objects, but has anyone done it for the human body?

Also, it's just amazing, when you consider the type of impact and other everyday accidents, that our bodies are strong and flexible enough to come out of such an incident with little more than a visible wound, some localised pain, a few strong words and a resolution to pay more attention in future :DDD

Please share your thoughts/answers on the F=ma question, I'm genuinely curious to know if there is any data available!

 Tags:

   Report

2 ANSWERS


  1. yes


  2. Good question.

    I don't know the answer, but took a shot anyway (even though my physics was long ago and mostly forgotten).

    What do you suppose a foot weighs?  1 kg?

    How fast is it moving when it strikes the door? 4 mph march time would be about 6.4 km/hr.

    How long is the foot in contact with the door?  This I have no idea.  I see them use a very short time for the old plane/duck collision example, but when I simulated this counting "one one-thousand" I got to about "one ...ouch" so I'll use 1/10 of a second.

    Then [1kg 6400 m/hr (1hr/3600s)]/ (1/10 s) = 18N ?

Question Stats

Latest activity: earlier.
This question has 2 answers.

BECOME A GUIDE

Share your knowledge and help people by answering questions.