Question

why is it difficult to hold a school bag having a strap made of a thin and strong string ? ( give answer fast)

Answer 1

it is difficult to hold a school bag having a strap made of thin string as compare to broad string as the thin string have less surface area so the pressure will more than the strong strips as

surface area is inversely proportional to the pressure........

Answer 2

Because of the mass of the bag pull down. The gravitational force are there. So they have strong string.