Newton's 3 Laws of Motion
Newton's first law of motion says that a moving object will keep moving, or that an object at rest will stay at rest unless acted upon by an unbalanced force; in other words, it describes inertia. For example, a soccer ball sitting on the ground won't move unless someone kicks it.
Image 1 illustrates this law with a flowchart. Using the soccer ball example, the ball will stay at rest until it is acted upon by an outside force, such as being kicked.
Newton's second law of motion states that force equals mass times acceleration, or F=ma. For example, a big, low-acceleration glacier or a small but quickly accelerating bullet will have a strong force. However, a small and slowly accelerating object (or for that matter a decelerating object) won't have much force. A big and rapidly accelerating object like an airplane has a huge force.
Image 2 shows that force and acceleration are closely related. Also, for equal masses a greater force provides greater acceleration.
Newton's third law of motion explains that for every action there is an equal and opposite reaction. This is why it hurts when you stub your toe. When your foot pushes on whatever you stubbed your toe on, that object pushes back on your toe and it hurts. Therefore, the harder you kick something, the harder it pushes back and the more your toe hurts. Another example of this law would be a rocket engine thrust as shown in Image 3.