Reference Notes | SLC
Gravitational Field and Gravitational Field Intensity
For: Science Class 10
The space around a mass over which it can exert gravitational force on other masses is called the gravitational field of the mass. The gravitational field intensity at a point in the gravitational field is defined as the force experienced by unit mass placed at that point. Its unit is N/Kg.
I = F / M ——— (a)
I = GM / d2 ——- (b)
I = GM / G2 ——- (c)
Gravitational field intensity I and acceleration due to gravity g are one and the same thing, so
W = ml ———— (d) [As W = mg]
Mass:
The amount of substance contained in a body is called the mass. The mass of the body is measured by using a physical balance or beam balance. It unit if kg in SI. The mass of the body is dependent upon the number of atoms and average mass of atoms present in the body.
Weight:
The weight of a body is defined as the force with which it is attracted towards the center of the earth. SI unit of weight is Newton (N). Its value changes from place to place as it depends on the acceleration due to gravity (g). It is a vector quantity.
W = mg ——- (a)
Weightlessness:
The weightlessness of a body is the state in which the body experiences that the body is not being attracted by any force
Freefall:
If a body is falling freely under the action of gravity alone neglecting air resistance, the motion is called freefall.
Differences between g and G:
G | G |
It is the acceleration produced on the body due to gravity | It is the force of attraction between two unit masses separated by 1m distance |
Its unit is m/s2 | Its unit is Nm2/kg2 |
It is a vector quantity | It is a scalar quantity |
Its value changes from place to place. | It is universal and is fixed |
Differences between Gravitation and Gravity:
Gravitation | Gravity |
It is universal force | It is not universal |
It occurs between any two bodies in the universe | For this one body must always be a planet or a satellite |
Differences between Mass and Weight:
Mass | Weight |
It is the amount of substance contained in a body | It is the force by which a body is attracted towards the center of the earth |
It is a constant quantity | It varies from place to place |
It is a scalar quantity | It is a vector quantity |
Its unit is Kg | Its unit is N |
It is measured by beam balance | It is measured by spring balance |