Question

Why it is difficult to carry a school bag with thin strap

Answer 1

It is difficult to carry a school bag with thin strap because the strap may get broken to the heavy weight of the books and copies .

Answer 2

It is difficult to carry a school bag with thin strap because the area of contact decreases and the pressure on the shoulder increases ( pressure=force/area). So it is adviable to wear school bags with broad straps