Define pressure. Give its SI unit.
The total force applied per unit area is called pressure.
Mathematically,
Pressure (P) = Force (F) / Area (A)
Its SI unit is pascal (Pa).
Why is it difficult to walk on the graveled roads?
As we all know that, P = F/A so, P ∝ 1/A
In the graveled roads, there are many sharp-edged stones on the surface. While walking on it, more pressure is exerted by the sharp stones (due to less area) and it causes pain and difficulties while walking on the graveled roads.