Question

What do we call the gravitational force between the earth and an object?

Answer 1

- Hint- Here, we will proceed by defining the gravitational force between two objects. Then, we will be writing down Newton’s Universal Law of Gravitation. This will tell us the factors on which gravitational force depends.

Complete step-by-step solution -

The gravitational force is a force that attracts any two objects with mass. We call the gravitational force attractive because it always tries to pull masses together, it never pushes them apart.
According to Newton's Universal Law of Gravitation, the gravitational force between two objects is given by
${\text{F}} = \dfrac{{{\text{G}}{{\text{m}}_1}{{\text{m}}_2}}}{{{{\text{r}}^2}}}$
where F is the force of gravity (measured in Newton, N), G = 6.67$ \times {10^{ - 11}}$ $\dfrac{{{\text{N}}{{\text{m}}^2}}}{{{\text{k}}{{\text{g}}^2}}}$ is the gravitational constant of the universe and is always the same number, ${{\text{m}}_1}$is the mass of one object (measured in kilograms, kg), ${{\text{m}}_2}$ is the mass of the other object (measured in kilograms, kg) and r is the distance between those objects (measured in meters, m)
Clearly, the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. Gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.
The gravitationalal force between the earth and an object is called the weight of the object. It is also equal to the product of acceleration due to gravity and mass of the object.
The weight of any object, w = mg where m is the mass of the object and g is the acceleration due to gravity for the earth (g = 9.8 $\dfrac{{\text{m}}}{{{{\text{s}}^2}}}$).

Note- The Moon's surface gravity is about 1/6th as powerful or about 1.6 $\dfrac{{\text{m}}}{{{{\text{s}}^2}}}$. The Moon's surface gravity is weaker because it is far less massive than Earth. The value of acceleration due to gravity g is affected by the altitude above the earth’s surface, the depth below the earth’s surface, the shape of the earth and the rotational motion of the earth.