He is trying to impress you be making himself look strong by pretending to feel no pain.
Usually it mean's she wants the D.
Then he has a thing for you girl.
Your classmate may be showing affection by punching you in the arm.
She likes you.
no it means hes a player
The way you could measure the mass of your arm is to place it in a tub of water that is filled to the brim, and then measure the amount of water that is displaced (spilled over) after you submerge your arm. That would give you a close estimate. But, when you punch, it is more than the mass times acceleration that is delivered, like in Newton's Second Law of Motion. If you watch Bruce Lee punch, you can see that he used his whole body and thrust his hips into the punch.
Like normal punching but move your arm faster
It means he has a crush on that girl.
sometimes guys punch you in the arm not a hard violent punch a little love tap!
Then she has jealous issues. Arms are safe territory I would say.
arm y it mean arm
The girl who played Bethany Hamilton? Yes. The arm stump was digitally added