1. Ms. Moore 10/1/12

2.  Energy is required for any change that occurs, no matter how small.  Energy is the ability to cause change.  Examples:  Forms of energy:  Electrical  Chemical  Radiant  Thermal  Energy can be stored and move from place to place.

3.  Kinetic energy (KE) is the energy a moving object has because of its motion.  The kinetic energy of a moving object depends on an object’s mass and its speed. Kinetic energy (joules) = ½ mass (kg) x speed 2 (m/s)

4.  A baseball with a mass of 0.15kg is moving at a speed of 40m/s. What is the baseball’s kinetic energy?  A sprinter has a mass of 80kg and a kinetic energy of 4,000 J. What is the sprinter’s speed?  A car with a mass of 1,500kg doubles its speed from 50km/h to 100km/h. By how many times does the kinetic energy of the car increase?

5.  Read the mini lab found on page 103.  Create a table of your results and be ready for a discussion.  How did the take off speed of the nickel depend on the distance that you stretched the rubber band?  How did the KE of the nickel depend on the distance the rubber band was stretched?

6.  Energy doesn’t have to involve motion. Motionless objects have energy.  Potential energy (PE) is stored energy due to position.  Examples:

7.  Elastic potential energy is energy stored by something that can stretch or compress  Rubber band or spring  Chemical Potential Energy is energy stored in chemical bonds  Food and gasoline

8.  Gravitational Potential Energy (GPE) is energy stored by objects due to the position above Earth’s surface.  Depends on the objects mass and height above the ground. GPE (j) = mass (kg) X 9.8 (m/s 2 ) X height (m)

9.  Find the GPE of a coffee mug with a mass of 0.3kg that is on a counter top 1m high above the ground.  How high above the ground is a baseball with a mass of 0.15kg that has a GPE of 73.5J?  A rock climber is 200m above the ground and has a GPE of 117,600J. What is the rock climber’s mass?

10.  Why do bouncing balls stop bouncing?  Refer to page 106  Measure tennis ball vs. bouncy ball  Include a table of results