Why is it difficult to hold a school bag having a strap made of a thin and strong string?
Answer
We know that
Pressure = Force/Area
In case of a thin strap of bag,
the area of the strap is less.
Hence, the pressure exerted on the shoulders is more.
In case of a thick strap of bag,
the area of the strap is more.
Hence, the pressure exerted on the shoulders is less.
That is why in case of a thin strap, the pressure exerted on the shoulders is more and hence it is difficult to hold such a bag.