Newton’s First law:
An object at rest
will remain at rest unless acted on by an unbalanced force. An object in motion
continues in motion with the same speed and in the same direction unless acted
upon by an unbalanced force.
This law is often called "the law of inertia".
In simple terms, there is a natural
tendency of objects to keep on doing what they're doing. All objects resist
changes in their state of motion. In the absence of an unbalanced force, an
object in motion will maintain this state of motion.
Newton’s Second law:
Acceleration is
produced when a force acts on a mass. The greater the mass (of the object being
accelerated) the greater the amount of force needed (to accelerate the object).
The Second Law gives
us an exact relationship between force, mass, and acceleration. It can be
expressed as a mathematical
equation: F = ma
or
FORCE = MASS times ACCELERATION
A car weighs 1000 kg.
You are pushing the car with an acceleration of 0.05 m/s2
Using Newton’s
second law, the force you are applying to the car is:
F = 1000 * 0.05
Newton’s Third law:
For every action
there is an equal and opposite re-action.
This means that for
every force there is a reaction force that is equal in size, but opposite in
direction. That is to say that whenever an object pushes another object it gets
pushed back in the opposite direction equally hard.
Example: The
rocket's action is to push down on the ground with the force of its powerful
engines, and the reaction is that the ground pushes the rocket upwards with an
equal force.
source: teachertech