Elements of Newton’s 2nd Law


List of Links

Newton’s Second Law

Now that we have the fundamentals of calculus, position, velocity and acceleration in place, it’s time to start putting forces and mass into the equation. Newton’s Second Law states that the sum of all forces acting on a particle produce an acceleration inversely proportional to its mass, \( m \).

$$\sum_j \vec F_j = m \vec a. $$

On this page we talk about force and mass in effort to complete the picture. Then we start thinking about the consequences of Newton’s Second Law.


pdflogoSimply put, forces are things that push or pull on an object. Usually, forces on an object come from direct contact with other objects. If it’s not a push or pull, it’s not a force. It’s not uncommon for novice dynamics students to velocities or momenta on a free body diagram, a place reserved only for forces. In the attached document, I discuss the most common types of forces we encounter in this class: gravity, springs, friction, and normal forces. Pay close attention to the difference between static and kinetic friction, these can be tricky.

Mass (It’s not the same as weight)

What is mass? This is a question that trips up a lot of students. First of all, mass is NOT weight. In this video, we define mass and distinguish it from weight. (Here is a direct link to the video, if you prefer.)

Mass (It provides inertia)

In dynamics problems, the mass of an objects provides inertial. I explain in this video. (Here is a direct link to the video on You Tube if you prefer.)

Qualitative Problems

Multiple Choice Concepts

Thumbnail link for concept problems

Basic Plotting (Coming soon)


 thumbnail link to concept problems with ramps  Thumbnail to concept problems with ramps

Blocks on Belts

Thumbnail link to block and belts problems thumbnail to concept problems of blocks on belts  thumbnail to conceptual problems with blocks on belts

Slope Sliders

Link to page of slope slider problems

 Analytical Problem Solving

Objects on Ramps

Problems with Friction

link to page of 1d friction problems