Question

What is gravitational force. Why does weight differ from place to place where mass remain same ?

Answer 1

$\mathsf{\huge{Answer}}$

$\bold{What\:is\:gravitational\:force?}$

Gravitational force is the force by which every object which have mass or energy are attracted towards each other.

For example : - an apple falling from a tree is attracted towards the centre of the Earth.

$\bold{Why\:does\:weight\:differs?}$

Weight is a force by which an object is attracted towards the Earth. But mass is the content present inside the matter.

Weight is differ in $\bold{Earth}$ because Earth is not a perfect sphere. It's radius is greater at equatorial regions and lower in polar regions.

As, Weight = Force

Then, W = mg

As, F = mg

Here, the mass will be always same everywhere as it is the content present inside the matter. But acceleration due to gravity 'g' will change as there is a change in the radius of the Earth.

Let's consider an example for our understanding.

Let an object of mass 2 kg is falling from a height at the equatorial region.

=> So, the radius is increased in the equatorial region, then the acceleration due to gravity will also change.

=> We take the appropriate value of the 'g' as $9.8 m/s^2.$ But as the radius is increased we have to take a decreased value. So, let's take 'g' as $9.8 m/s^2.$

=> Therefore, W = mg

W = $2kg \times 9.8 m/s^2$

$\bold{W\:=\:19.6\:N.}$

Take the same example, but in the polar region.

As the gravitational force is indirectly proportional to the square of the radius.

Now, the radius is decreased so, the value of 'g' will increase. So, let's take, 'g' = $10 m/s^2$

Now, W = mg

W = $2kg \times 10$

$\bold{Therefore,\:W\:=\:20\:N.}$

Thus, if we compare case I and case II, we will observe that,

$\bold{Case\:II\:>\:Case\:I}$

But in different planets the radius is different as compared to Earth. Thus, the acceleration due to gravity will also change. Thus, the weight will also change. But mass is the content present inside the matter, hence, it will not change.

Answer 2

$\Huge\star\sf\textsf{Gravitational force is a natural phenomenon by which the things having mass/energy are brought towards one another}$

$\Large\star\sf\textsf{it is true that weight differ from place to place, for example:- Weight is more at the poles and weight is less at the equator}$

$\large\star\sf\textsf{It is because earth is not a perfect sphere in shape, at some places it is smooth/plain and at some places it is rocky/bumpy.At poles it is nearer to the centre of the earth and at equator, it is far from the centre of the earth and we know that, the nearer an object is to earth/centre of earth, the more the gravity/gravitational force acts on the object}$