Newton's First Law
Newton's first law of motion is sometimes called the law of inertia. It states that an object at rest tends to stay at rest and an object in motion tends to stay in motion in a straight line at a constant velocity unless acted on by an outside force.
In other words, if there are no outside forces, an object will keep doing what it is currently doing. If it's moving, it will continue to move at the same velocity. If it is not moving, it doesn't want to start.
That's why it's sometimes referred to as the law of inertia. In simple terms, inertia (which is related to the mass of an object) is a measurement if the laziness of an object. It doesn't want to change. Rather it wants to keep doing what it's currently doing.
Newton's first law is a statement of the principle of inertia.
Newton's first law states that in an inertial frame (a frame of reference moving at constant velocity), objects at rest will stay at rest and objects moving at a constant velocity will continue doing so.
Inertia is a body's natural resistance to any change in its motion, which includes changes to its speed and direction.
When you compare the two, you find that they are equivalent statements!
Well, there is no inertia mass (unless you meant inertial mass) but mass can have inertia.
This is Newton's first law of motion. It states that an object at rest will stay at rest and an object in motion will stay in motion unless acted upon by an external force.
An example is when you are in a car and it stops very fast. You keep going forward a little but the seat belt stops you. So you became an object in motion and you kept staying in motion until an external force, the seat belt, acted upon you by stopping you.
This all works similarly in the world. A bullet will keep staying in motion relatively the same. But when you factor in air resistance and gravity, you see that those are the external factors. Air resistance slowly stops the bullet and gravity makes it hit the ground eventually, where it stops.
Equilibrium is the state in which the sum of all the forces on a body (the net force) and, independently, the net torque are equal to zero. In addition, if both the linear and rotational velocities are zero (in some frame of reference), we say that the body is static with respect to that frame.