# Forces and Inertia

One of the most important steps in solving dynamics problems in physics is understanding the concepts of forces and inertia.

Forces are any influence that will change the motion of an object. These influences result in the interaction of the object with another object or its surroundings.

F = m a

F = force

m = mass

a = acceleration

This is Newton’s (Second) Law

examples: frictional force, gravitational force, tension force, electrical force, normal force, spring force, any applied force, etc.

Understanding the different types of forces, how they interact, and when they are present will help in creating your Free Body Diagrams when solving your dynamics problem

## What is Force (~5 minutes):

Inertia is an object’s tendency to resist a change in its motion (speed, direction, etc.)

This is Newton’s (First) Law

example: think of inertia as trying to push a bowling ball vs. a ping pong ball with your pinky finger, suddenly hitting the breaks in a car, being on an amusement park ride and hitting a really sharp turn