Chapter 12: Work and Energy

Work and Power What is Energy? Conservation of Energy

Overview

What is work?◦ A force through a distance.

Is it work?◦ You sitting in class.◦ A person shot putting.◦ Picking up your phone.◦ The Hulk throwing Loki around

Work

Individually write down five examples of work and five examples of non-work.

After I tell you to share your examples with your partner.

Then we will bring it up as a class.

Concept Check

Work as stated is a force through a distance.◦ W = F x d

The units for work are the joule.◦ N x m= J◦ Unit for all types of Energy

Calculating Work

Imagine a father playing with his daughter by lifting her repeatedly in the air. How much work does he do with each lift, assuming he lifts her 2.0 m and exerts an average force of 190 N?

Sample Problem

Page 379 p. 1-5

Practice

Running up a flight of stairs doesn’t require more work than walking, but it is more exhausting.

The unit used to measure work in relation to time is called power.

Power = work/time P=w/t

Power is measured in watts (W)

Power

Pg. 381 #1-5

Practice