Inertia
It is the property of a mass that resists shifting from its movement.
The inertia of an entity refers to the object ‘s reluctance to continue moving if it firstly stays stationary or to the object ‘s reluctance to stop moving if it first moves.
If a body of matter is set, it takes power to move. The greater the mass, the greater the power. We say loads of people have inertia: they are hesitant to travel.
Mass
The mass (m) of a body is a measured measure of its inertia, i.e. its resistance when a force is applied to a transition in the rest state or movement of the body.
The kilograms (kg) is the SI unit of mass. It’s an unparalleled number.
The bigger a body mass, the lower the rate of motion change.
Matter is the underlying substance that creates the visible world and forms the source of all empirical phenomena along with electricity. Atoms are the central building blocks of matter. Nucleus and electrons are the atoms themselves.
Read also: LOGIC GATES
Amount of Substance
While mass is characterized by inertia, the standard understanding is that:
The mass (m) of a body is a measure of its quantity in the body.
Matter does not alter in ordinary conditions. The quantity of the element should also be considered to be equal to the mass in the body. If the quantity splits, we can presumably still halve the quantity.
A beam balance, or an electronic balance, may be used to calculate the force.
Gravitational Force
Any two bodies in the cosmos forcefully draw one another. The magnetic force is called this phenomenon. This enticing force is known as the gravitational force or gravity force.
An area of force is a zone where a body is influenced by the existence of some other body or bodies.
A field of force is therefore a way to portray how bodies can affect one another.
Gravitational Field
A gravity field is an area in which a mass is highly attracted by gravity.
An area of space around a body with the property of a mass is a gravitational field. Any other body with mass would feel an intensity of attraction in this area.
Anybody near the earth’s surface is attracted by the Planet gravity.
You feel weight on earth from the gravity of the earth. Below is the formula for weight determination.
Gravitational Field Strength
Both things set a field of gravity around themselves. If a second body is positioned X away from the first body, the enticing force against the first body would be gravitational.
At any point in a gravitational field, the gravitational force per unit mass on any corpse put at that point is gravitational field strength (g).
Newton per kilogram is the Gravity Field SI Unit. (N kg002N kg−1)
Fg=mgFg=mg
Where
FgFg = force of gravity (unit N),
m = weight (kg unit),
g = power of the gravity field
Its direction is to the rigid body, like the Earth, which establishes the field of force.
The strength of the gravity field on the planet is about 10 N kg−110 N kg−1, although the strength of the pressure field on the planet is just 1616. Therefore, you can experience only 1616 the Moon weight.
Weight:
 The Earth’s magnetic field induces magnetic of all material bodies near the Earth’s surface. This influence of gravity is generally called weight.
 The weight (W) of a body is the gravity of the Earth.
 Newton (N) is the SI unit of weight. It’s a number of vectors.
 It is moving throughout the middle of Earth or is generally referred to as downwards vertically.
 A newton meter is used to calculate weight.
Your weight varies very significantly on Earth – you will weigh 3 N heavier than one above the equator in the northern poles. This is because the gravitation field power of various areas of the world is significantly DIFFERENT.
Typically, in your equations you ignore this disparity. (For the Planet to be slightly distorted at the poles if you like to wonder if it was thicker at the poles.)
Density:
Volume (V) is defined as the amount of space occupied by a threedimensional object as measured in cubic units.
SI unit of volume is meters cube (m3m3). It is a scalar quantity.
Density (ρρ) is defined as the mass (m) of a substance per unit volume.
SI unit of density is kilograms per meter cube (kg m^{3}). It is a scalar quantity.
Another common unit of density is g cm−3g cm−3.
Note: 1000 kg m−3=1 g cm−31000 kg m−3=1 g cm−3
Density is given by:
ρ=mVρ=mV
The density of a substance does not change as you move from place to place as the mass and volume does not depend on the gravitational acceleration of the point that the object is at.
Read also: D.C Circuits
Differences
Mass  Weight  Density 
· Mass of the substance is the amount of matter or quantity of matter it contains. It is an essential property of a material body and therefore for a material body it can never be zero. It is not affected by the presence of other bodies. Further, it does not vary with change in temperature, pressure or the location of the body in space.
· Mass of a body is of two types: (Inertial mass, gravitational mass) · When a body is in translational motion under the effect of an external force other than gravity, the mass of the body measured is called inertial mass.
· It is found that if a given force produces an acceleration a1 in a body of mass m1 and a2 in a body of mass m2, then · m1/m2 = a2/a1

· Weight of a body is defined as the gravitational pull of the earth on it
· The weight of a body of mass M is given by
· W=Mg
· Weight of the body may vary from place to place and it may become even zero. E.g. weight of a body becomes zero at the center of the earth. Thus, it is not essential property of the body
Note:
gram and kilogram are not the units of weight. Weight is measured in gram force (gf) or dyne in cgs system and kilogram force(kgf) or newton(N) in mks system. 
· Density of a substance is its amount of mass per unit volume. So, density is the property which relates the mass of an object divided by its volume. The units of density may be obtained as
· Density = mass/volume
· As we know that volume of a substance changes when heated or cooled, therefore, densities depend upon temperature. Hence, while reporting a density the temperature must also be mentioned.
