$(a)$. Define pressure. What is the relation between pressure, force, and area? State the units in which pressure is measured.
$(b)$. Explain why school bags are provided with wide straps to carry them.

(a).  Pressure: The force acting upon the per unit area of any object.

 The relation between pressure, force and area:

$\boxed{P=\frac{F}{A}}$

Here, $P\rightarrow$ pressure

$F\rightarrow$ force

$A\rightarrow$ area

The SI unit of pressure is $N/m^2$ or $Pascal$.

(b). School bags are provided with wide straps to carry them to increase the area of contact with shoulders to reduce the pressure on the shoulder. It is because the pressure is inversely proportional to the area of the surface.