1. Chapter 12 Work and Energy
Section 1
Work, Power, and Machines
p. 378

2. Understand simple machines
Objectives
Understand simple machines
Evaluate the relationship between energy, work, and power

3. I. Work- transfer of energy to a body by the application of a force that causes the body to move in the direction of the force
A. W=F x d – for work to take place
there must be movement
B. Measured in Joules
1 J = 1 N x m = 1 kg x m2/s2
II. Power – the rate at which work is done or energy transformed
A. Power= work/time P= w/t
B. Measured in watts W=J/s

4. III. Machines and Mechanical Advantage
A. Machines multiply and redirect force
B. Mechanical Advantage- how much a
machine multiplies force or increases
distance
1. Ratio between output force and
input force
2. Ratio between input distance and output distance (if friction is ignored- ideal mechanical advantage)
3. MA = output force/input force = input distance/output distance

5. Homework
Stairs worksheet
Read 12.1 and 12.2