1. Chapter 4 Physics A First Course Energy and Systems

2. Energy and Systems Machines, Work, and Energy 4.1 Work and Power 4.2 Simple Machines 4.3 Efficiency

3. 4A Investigation: Force, Work, and Machines Key Question: How do simple machines affect work? *Students read text section 4.1 AFTER Investigation 4A

4. 4A Investigation Topics Build and use a simple machine (ropes and pulleys). Measure input and output forces in a simple machine. Measure input and output distance in a simple machine. Calculate mechanical advantage. Calculate input and output work.

5. Chapter 4.1 Objectives and Vocabulary power watt horsepower Define work in terms of force and distance and in terms of energy. Calculate the work done when moving an object. Explain the relationship between work and power.

6. 4.1 Work done against gravity W = mgh height object raised (m) gravity (m/sec 2 ) work (joules) mass (g)

8. Chapter 4.2 Objectives and Vocabulary machine input output fulcrum simple machines mechanical advantage input arm output arm tension Describe how a machine woks in terms of input and output. Define simple machines and name some examples. Calculate the mechanical advantage of a simple machine given the input and output forces.

12. 4B Investigation: Conservation of Energy Key Question: How does a system get energy? *Students read text section 4.3 AFTER Investigation 4B

13. 4B Investigation Topics Measure the work done for a car on a track. Graph forces versus distance for a car on a track. Derive the formula for the speed of the car from force and mass data. Predict the speed of the car given a force.

14. Chapter 4.3 Objectives and Vocabulary efficiency reversible irreversible Describe the relationship between work and energy in a simple machine. Use energy conservation to calculated input or output force or distance. Explain why a machine's input and output work can differ.