Question

Why do load-carrying heavy vehicles have a large number of wheels?

Answer 1

The pressure applied on a surface by an object increases as the weight of the object increases or the surface area of contact reduces. On the other hand, the pressure exerted decreases as the weight of the object decreases or the surface area of contact increases.

Formula used:
$P = \dfrac{F}{A}$ …………… (1)
Where $P$ is pressure, $F$ is Force, and $A$ is the surface area.

Complete step by step answer:
The pressure is directly proportional to the pressure, it is defined by the force in unit surface area.
$P = \dfrac{F}{A}$ …………… (1)
Where $P$ is pressure, $F$ is Force, and $A$ is the surface area.
From equation (1) we get the idea that if pressure and surface area are inversely proportional to each other. If the surface area increases then the pressure decreases and if pressure increases the surface area decreases. So higher the contact area between two surfaces lowers the pressure. So this is the reason since a higher number of wheels means a larger contact surface area so that the pressure on the road is reduced. Also, the large number of wheels also ensures that the weight of the load is distributed among the tires and no single tire is under stress.

Note:
Since pressure is calculated by dividing the force by area, it has units of Newton per meter squared $\left( {N/{m^2}} \right)$ , and this unit is given a new name, Pascals $\left( {Pa} \right)$ .
Walking in high heels is difficult compared to flats or wedges. It is because the high heels have less contact surface area compared to flats and wedges. Even though wedges and heels are of the same height still because wedges have more contact surface area than high heels so they are more comfortable and easy to walk.