What is the difference between stress and strain? What will be an ideal ...

Their shape and/or their volume are altered by the stress of an applied force that is greater than the
rock's internal strength.

Isaac Newton said that the force of gravity (F) between two masses (m1 and m2) is directly
proportional to their masses and inversely proportional to the square of the distance between their
centers of mass. This means that an attractive force exists between any two objects and the magnitude
of that force varies, depending on the masses of the objects and the distance between their centers.
Gravitational attraction would be the same everywhere on Earth's surface if the planet were perfectly
spherical, homogeneous throughout, and not rotating. But none of these things is true.

Continental crust is granitic with an overall density of 2.7 g/cm3, and oceanic crust is made of basalt
and gabbro with a density for 3.0 g/cm3. Continental crust is around 35 km thick, and in mountain
ranges, it's much thicker. Oceanic crust is only 5 to 10 km thick.