What is pressure and how it is calculated ?

Pressure is defined as the force divided by the area perpendicular to the force over which the force is applied, or. P=FA. A given force can have a significantly different effect depending on the area over which the force is exerted Pressure the effect of a force applied to a surface is a derived unit, obtained from combining base units. The unit of pressure in the SI system is the pascal (Pa), defined as a force of one Newton per square meter. The conversion between atm, Pa, and torr is as follows: 1 atm = 101325 Pa = 760 torr.

Explanation:

Pressure and force are related, and so you can calculate one if you know the other by using the physics equation, P = F/A. Because pressure is force divided by area, its meter-kilogram-second (MKS) units are newtons per square meter, or N/m2. If you convert an atmosphere to pounds per square inch, it's about 14.7 psi.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.