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Conservation of Energy. Activity. Kinetic Energy should equal Potential Energy. What do you expect to happen when you drop a ball from a surface to the ground? What should happen to your potential energy? How should your potential energy compare to your kinetic energy?.
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Activity • Kinetic Energy should equal Potential Energy. • What do you expect to happen when you drop a ball from a surface to the ground? • What should happen to your potential energy? • How should your potential energy compare to your kinetic energy?
What do we need to calculate Potential Energy? • Mass • Gravitational acceleration (9.8m/s2 ) • Height/distance
Step 1 • Measure the mass of the softball. • Measure the distance from the floor to the top of the counter/table/chair (whichever you decide to drop them from). • Calculate Potential Energy. • GPE = mgh • Remember energy is calculated in Joules!
Hmmm… • KE= ½ mv2 • If KE=PE, take the number you calculated for GPE and substitute it in this equation. Predict the velocity of the softball when you drop it.
What do we need to calculate Kinetic Energy? • Mass • Velocity • Step 2: • Drop the ball. • Time how long it takes to drop. • Record the Time. • Calculate Velocity (m/s).
Kinetic Energy • Calculate Kinetic Energy • KE= ½ mv2 • Compare your Kinetic Energy to your Potential Energy. • Calculate the difference between the values.
What happened? • How did your predicted velocity compare to your actual velocity? • How big of a difference was there between kinetic energy and potential energy? • What do you believe caused this difference?