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:
Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car go 0.05 m/s/s. Using Newton's Second Law, you can compute how much force Mike is applying to the car.
Answer = 50 newtons
1. Who was the scientist who gave us the Laws of Motion?
2. How many Laws ...view middle of the document...
What is another name for the first law of motion?
Answer: Law of Inertia
4. Which law explains why we need to wear seat belts?
Answer: First Law of Motion
5. Which law says that force is equal to mass times acceleration (F=MA)?
Answer: Second Law of Motion
6. Which law says that heavier objects require more force than lighter objects to move or accelerate them?
Answer: Second Law of Motion
7. Which law explains how rockets are launched into space?
Answer: Third Law of Motion
8. Which law says that for every action there is an equal and opposite reaction?
Answer: Third Law of Motion
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
"the law of inertia". 
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 motion in this picture?
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.
Now that you understand
Newton's First Law of Motion,
let's go on to his Second Law of Motion.
According to Newton's third law...
For every action there is an equal and opposite reaction. 
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