Summing Forces (Forces Part II)

Understanding the Summation of Forces

During the Dynamics Unit, one of the fundamental skills you have to develop is “The Summation of Forces” or the “Net Force” calculations. This skill is critical to your success in understanding how objects move and interact in our world, from cars accelerating down a highway to planets orbiting the sun and, everyone’s favorite, motion on an inclined plane. I will discuss this topic in this blog and explore its importance in everyday applications and physics problems.

What Is the Summation of Forces?

It's a fancy way of saying adding up all of the forces. ‘

The summation of forces is simply the total force acting on an object when all individual forces are combined. 

Σ F = Σ(ma)

Careful, we have a second Greek letter, Σ (Sigma). 

Remember that we are not intimidated by symbols, even ones from different languages.

In math, Σ means to add things up. However, be cautious. You first want to add the forces in the x and y directions separately. Then, combine the results to form a right triangle and solve for the resultant using Pythagorean’s Theorem and trigonometry (Sin, Cos, & Tan)

When summing the forces, it is important to know the following:

• If the object is at rest, Σ F =  0

• If the object is moving at constant velocity, Σ F = 0

• If the object is accelerating, either speeding up or slowing down, Σ F =  Σ(ma)

There are no other possible answers!!

If you need more help understanding these concepts, schedule an appointment by contacting me at Kevin@doyletutor.com.