How can a one-ton car drive over a person’s foot and not cause any significant damages?
In: Physics
A knife can cut so easily because the force that’s applied (which is not very large, you don’t need a lot of force to cut vegetables) is focused over a very sharp edge, a very very small area of contact. For stabbing, the entire force is focused down to a point; compare that with trying to stab someone with, say, a hammer, same force, a lot bigger area of contact.
So the tires of a car are basically “spreading the weight of the car” over the surface that makes contact with the ground. It’s why bigger cars, trucks, etc., have bigger or more tires, to “spread out the weight.”
So when a 1 ton car runs over your foot, it has 4 tires so any one tire only feels 1/4 of a ton, 500 lbs, and then, given the surface of that tire vs. the part that’s over your foot, you may only feel 200 – 250 lbs of that actually pressing on your foot, the rest of the tire presses on the ground around your foot.
So 250 lbs is the weight of a heavy person standing on your foot. It may hurt, but it’s not *that* bad.
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