WORK KINETIC ENERGY THEOREM

THE WORK ENERGY THEOREM

Up to this point we have learned Kinematics and Newton's Laws. Let 's see what happens when we apply BOTH to our new formula for WORK!1. The net work equation cosdFW netnet

maFnet

advv if 222

madWnet

2

22if vv

ad

2)( 22

ifnet

vvmW

2. Applying Newton's second law

3. Using Kinematic Eq’s

4. An interesting term appears called KINETIC ENERGY or the ENERGY OF MOTION!

2)( 22

if vvmW

The Work Energy Theorem

KEWnet

KEKEWnet

mvmvW

if

if

22

21

21

A 50kg person is riding a skateboard at constant velocity of 6m/s when they go up a 30o ramp.

1. How high will the person go? (ignore friction)2. What is the net force acting on the person before going up the ramp?3. What is the net force acting on the person while going up the ramp?

Conservative Forces: 1.Work does not depend

on the path2.Net work = 0; for a

round trip process; The PEi=Pef

3.Examples: Gravity and Spring forces

Non-Conservative Forces1.Work does depend on path2.Net work does NOT equal zero3.Examples: Push or Pull forces, friction