why school bags are provided with broad straps and not with thin straps?
The broad straps of school bags reduce the pressure on the shoulder or on the hand. We know,
Pressure = Force/Area
So, increasing the area decreases the pressure.
In case of thin straps the, the area is small and hence pressure is large. For larger straps the area is large thus reducing the pressure.
as we know that pressure acts more when the area is less and acts less when the area is more.in case of the school bags the broader straps provide more area due to which the pressue acting on the sholders is less and it is vice versa for thin straps.so it is comfortable to wear bags of broad straps.