All the engineering, design, and construction of things are based on the same laws of motion published by Isaac Newton over 300 years ago. Think about this the next time you go across a bridge, fly in an airplane, ride in a car, go inside a building, or drive through a tunnel. When engineers design bridges, they must know the maximum amount of force that the bridge must be capable of supporting, as well as the strength of materials involved. When skyscrapers are designed and built, the forces on the beams that hold the building up must be completely known. In addition to allowing us to design and build great things, studying laws of motion and forces on Earth gives us a better understanding of how the rest of the universe works. This is because the laws of motion we have on Earth are believed to hold for the entire universe.

Newton's 1st Law of Motion
An object in motion tends to remain in motion, and an object at rest tends to remain at rest, unless acted on by an outside force.

Newton's 2nd Law of Motion
The rate of acceleration of an object depends on the mass of the object and the force applied.

Newton's 3rd Law of Motion
For every action there is an equal and opposite reaction.

Momentum
When an object has a lot of momentum, a large force is needed to change its motion…