The focus of Lesson 1 is Newton's first law of motion - sometimes referred to as the law of inertia. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless upon by an unbalanced force.

acted

Explanation:

In order for something to start moving, you need to apply a force to it or something else needs to apply a force to it. That is the same for stopping an object, some force needs to stop it. It could be your hand or it could be gravity.

the body's situation won't change the forces are equal opposit and on the same body

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it