1. Warm Up 2/8/08 1) How much work is done when a 7 N force is applied to a box to move it 7 m? 2) Define Energy, and use it in a sentence.

2. Standards

3. Go over Quiz

4. Review Work: Remember work is force times distance. Another definition for work: Change in kinetic energy (K)‏ Kinetic Energy = ½ mv 2

5. Lab 1) Gather materials  Mass Cart, meter stick, paper, mass equal to the mass of the cart, Masking Tape, Stopwatch, pencil, Wood Board  2 Ring Stands 2) Measure 0.5 m and put tape where you started and ended 3) Make a ramp with your board, tilt it at 20 degrees 4) Start the front of your cart at a HEIGHT (NOT distance up ramp) of 10 cm. Release it and time how long it takes to travel the ½ m marked in tape.

6. Lab 5) Record this time and use it to find the velocity of the cart on level ground. 6) Repeat 3 times (and record)‏ 7) Repeat 4, 5, & 6 for a Height of 20 cm 8) Repeat 3, 4, 5, 6, & 7 for an angle of 35 degrees, 9) Repeat all of the steps after adding enough mass to the cart to double its total mass 10) record the mass of the cart alone, and twice its mass, and find the kinetic energy for each trial.

7. Examples 1. A 2 kg bird is flying at 25 m/s, what is the bird’s kinetic energy? 2. A 1000 kg car is traveling at 10 m/s, what is the car’s kinetic energy? 3. A 600 kg ostrich goes from traveling 10 m/s to 5 m/s, what is the change in the ostrich’s kinetic energy? 4. If a 2 kg object has 100 J of work done on it. How much will its velocity change?

8. Practice 1. A 7 kg bird is flying at 15 m/s, what is the bird’s kinetic energy? 2. A 2000 kg car is traveling at 13 m/s, what is the car’s kinetic energy? 3. A 400 kg emu goes from traveling 3 m/s to 7 m/s, what is the change in the ostrich’s kinetic energy? 4. If a 9 kg object has 400 J of work done on it. How much will its velocity change?

9. Homework pg 267 (1, 5, 7, 17-19, 36-39, 52)‏