Question

why is it difficult to hold a school bag having a strap made of a thin and strong string?

Answer 1

It is difficult to hold a school bag with a thin and strong string because its surface area is very small.

Answer 2

It is difficult to hold a bag having thin strap whereas the bag having wide strap is not difficult as thin this is because of pressure
$pressure = \frac{force}{area}$
may be it is helpful to uh