According to 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 |
What does this mean?
This means that 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.
Let's study the "skater" to understand this a little better.
What is the unbalanced force in this picture?
What happened to the skater in this picture?
This law is the same reason why you should always wear your seatbelt.
Newton's First Law of Motion,
let's go on to his Second Law of Motion.
According to 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). |
What does this mean?
Everyone unconsiously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.
However, the Second Law gives us an exact relationship between force,mass, and acceleration. It can be expressed as a mathematical equation:
or
FORCE = MASS times ACCELERATION
This is an example of how Newton's Second Law works:
Answer = 50 newtons
This is easy, let's go on to
Newton's Third Law of Motion
| | |
| |
or
FORCE = MASS times ACCELERATION
Answer = 50 newtons
According to Newton's third law...
For every action there is an equal and opposite re-action. |
What does this mean?
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.
Let's study how a rocket works to understand
Newton's Third Law.
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.
UP,
UP,
and
AWAY!
You have just learned about
Newton's Three Laws of Motion.
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.
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