Question

why do boxers put on glove? what is the physics behind it?

Answer 1

well  in  boxing  there is  about the  gloves 
power=impact=l=(mass* velocity(speed))/(area* time of impact)
 so the  heavier glove more power and  smaller glove  less  power
 here is the thing that mass and weight  as the total incredible gable so that answer
is easy
Force = Mass * Acceleration. 
this means that u have to apply more force to a heavy glove to get it moving at the same speed and the light glove. 
this will wear u out faster and make it harder lo land a punch since they will be slower. 
glove size just helps with defence too. 
so if you are a heavy weight with little stamina a pair of heavy small gloves to land one punch and end it. if you are a light that has stamina and a slower arm lighter gloves that are still small. 
if you are a light weight with slot of stamina the a light glove that small will be best. you have to find your balance between mass and glove size. that is the key!