May 2, A ball can experience 30 J of work if it falls off the counter. How massive is the ball if it is at a height of 2 m? 2.How much PE does the ball have sitting on the edge of the counter? KE?

Relationships Potential Energy –Directly related to height –Directly related to mass –Directly related to weight Kinetic Energy –Directly related to mass –Directly related to VELOCITY SQUARED

Q: What is the Law of Conservation of Energy This is similar to the Law of Conservation of Mass/Matter! The Law of Conservation of Energy says energy cannot be created or destroyed, but it can be transformed from one form to another.

Forms of energy: »Mechanical (Motion- includes sound) »Heat (friction) »Electromagnetic (includes light and electricity) »Chemical »Nuclear

Energy Transfer –Energy moves from one object to another –ex. Boiling water on stove Energy Transformation –Energy changes from one form to another –Ex. Light  heat

Examples of Energy Transformations: Ex) On a roller coaster ride all of the energy for the entire ride comes from the conveyer belt at the beginning of the ride. –This energy is then stored as GPE at the top of the first hill. –As the coaster travels down the first hill, the GPE is converted to KE. –In the real world, a small amount of this energy is lost as heat to the wheels and vibrations that produce the roaring sound!

KE + PE = Total Energy –At the top of a hill, KE = 0 J. All energy is PE. –At the bottom, all the energy that was PE at the beginning has been changed into KE. (so now PE = 0 and all energy is KE)

Homework Parts 3 & 4 Part 5, #s 1 – 8 –# 3: You must take orginal height and SUBTRACT what you calculate in the formula to get the new height –#6: Use formula for final velocity (Vf = at + Vi)