THE LAWS

FIRST LAW: INERTIA

An object remains at rest, or in uniform motion in a straight line, unless compelled to change by an external force.

SECOND LAW: F=MA

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force.

THIRD LAW: ACTION/REACTION

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

Problem-Solving Technique

Part 1: Understand the physical situation

This is the most important part of the problem-solving process in arguably any mechanics problem. Before you start writing any equations, you should always try to have at least a basic understanding of what is actually happening. This includes things like where the net direction of acceleration is, and what forces are acting where in a Newton's law problem.

Doing this requires drawing of the diagrams. Draw free body diagrams for each object involved, as well as the system as a whole

Things to consider:

Do not forget about reaction forces

When looking at a system as a whole, you do not need to consider internal forces

Only write your equations with forces acting directly on the object in question

Part 2: F=ma statements and solving

Often in difficult problems, algebra can be the biggest time waster. Although the best way to overcome this is through practice, here are some tips when writign your f=ma equations

1) Write out your F=ma equations in an organized fashion -- This is really helpful because if you can easily reference your equations, it is much faster to make substitutions and achieve your desired result.

2)Label your forces clearly. If your forces are indecipherable you will definitely get confused in the algebra

3) Be very clear about what you are solving for. If you are solving for the acceleration of the system think about what equations make it easiest to reach there. What variables do you not need?