Variation of Acceleration due to Gravity

Variation of 'g' on the poles & equator.

We know that the shape of the earth is not completely spherical rather it is oval as shown in the figure.

Due to this, the polar radius (R_p) of the earth is less than the equatorial radius (R_e).

i.e. R_p < R_e

Since acceleration due to gravity (g) is inversely proportional to the square of radius, the value of g is more at poles & less at equatorial region.

i.e.,g_p > g_e Because R_p< R_e

Since g_p > g_e the weight of an object on poles is greater than on equator.

The weight of object at Solukhumbu and Janakpur:

The weight of the object is greater at Janakpur.

It is because weight of the body is directly proportional to acceleration due to gravity and acceleration due to gravity is inversely proportional to the radius plus height squared from sea level

i.e. w ∝ g and g ∝

AsSolukhumbu lies at thehigher altitude than Janakpur, the value of g is less at Solukhumbu and accordingly the weight is less at Solukhumbu than Janakpur.

Feather and Coin experiment

The main conclusion of feather and coin experiment is that the falling rate or acceleration due to gravity is independent of the masses of the falling bodies.

OR

If there is no air resistance than all the bodies fall together irrespective of their masses.

Fig 1.7 Coin and feather experiment

When a coin and a feather are freely falling in presence of air the air resistance experienced by each object is different as they have different size and structure. So they fall at different rate which is less than 9.8. But in absence of air there is nothing to resist their falling so they fall at the same rate 9.8