1. Understanding Concepts
Work and Energy Review
Understanding Concepts

2. Work Done by a Constant Force
Recall that
where work is measured in joules (J)
So, what is work really?

3. Now, lets put this all together….
Work Cont’d
As the equation suggests, work is simply how much force is being applied to an object over a given displacement. But why is this important?
Recall that an applied force is simply a measure of how much each unit of mass is being accelerated. Also, an accelerated object must experience a change to its momentum (Inertia).
Now, lets put this all together….

4. Work-Energy THM
So, as we just saw, work and energy are one and the same thing. However, more accurately described, we say that:
Energy is an objects ability to do work
In terms of Kinetic Energy and Work: or

5. Where the direction of the force is opposite that of the displacement.
Work due to Friction
Another common form of work done, one you haven’t discussed thus far, is the work done due to friction. Mathematically, this is defined as:
Where the direction of the force is opposite that of the displacement.