When we jump on a concrete surface , the feet gets injured, why?

Because the gravity pulls use towards the ground and our bones can’t take the amount of weight hitting the surface

What part of your body hits the ground first?

Your legs, knees and torso can flex and accommodate some deceleration, but when you go airborne, even briefly, you accelerate downward, and that in effect increases the “weight” your body must suddenly bear in impact.

Try this at home. Get something heavy, like a box full of paperback books. Now, take go up two steps, turn around, and carefully step over the first step directly onto the ground.

Your feet really notice it don’t they. Maybe even sting a bit.

Now imagine you missed that first step accidentally, and your foot slammed down an additional 8...(more)

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

are you like autistic or something?

xd