PSc.3.1.2Energy Notes

EQ: How are kinetic energy and potential energy related?EQ: What is the law of conservation of energy?

Vocabulary

Word Dictionary Own Words Picture/Motion

Mechanical system

A mechanical system manages power to accomplish a task that involves forces and movement.

Something that has to do with forces and motion

Kinetic Energy energy that a body possesses by virtue of being in motion.

Energy caused by motion.KE = 0.5mv2

Potential Energy

the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.

Energy that relates to the height of an object.PE = mgh

Conservation of Energy

a principle stating that energy cannot be created or destroyed, but can be altered from one form to another.

Energy changes form, but is not made or destroyed.

Heat the quality of being hot; high temperature.

How hot something is

Friction the resistance that one surface or object encounters when moving over another.

Opposes a motion

Kinetic Energy-The energy caused by motion.-KE = 0.5mv2

-The unit for energy is Joules (J).-The two factors that affect kinetic energy are mass and velocity.-When did your balloon rocket have kinetic energy?-Where did you see the highest kinetic energy on your skate park?

-Where did you see the lowest kinetic energy on your skate park?

1. What would be the kinetic energy of bird with a mass of 20 kg and a velocity of 6 m/s?  

2. What would be the kinetic energy of a skater with a mass of 5 kg and a velocity of 12 m/s? 3. Which would have a higher kinetic energy?  

A. A roller coaster with a mass of 50 kg and a velocity of 10 m/s. B. A roller coaster with a mass of 10 kg with a velocity of 20 m/s. C. I need more information to answer.

-Answer: _______ because ____.

Potential Energy

-The energy caused by position (or height).-PE = mgh (g = 9.8 m/s2)-The unit for energy is Joules.-The three factors that affect potential energy are mass, acceleration due to gravity, and height.-When did your balloon rocket have potential energy?

1. What would be the potential energy of bird with a mass of 20 kg and is flying 30 m above the ground?

2. What would be the potential energy of a skater with a mass of 5 kg and isat the top of a halfpipe, 100 m above the ground?

3. Which would have a greater potential energy?  A. A roller coaster with a mass of 50 kg and a velocity

of 10 m/s and near the top of a hill.  B. A roller coaster with a mass of 50 kg with a velocity

of 20 m/s and at the bottom of a hill. C. I need more information to answer.

-Answer:

-Which would have a greater potential energy?A. An owl in a tree that has a weight of 10 N.B. An owl on the ground that has a weight of 20 N.C. I need more information.

Conservation of Energy-Energy is not created or destroyed, it just changes form.

-The total energy is called mechanical energy (because we are dealing with a mechanical system).-When friction is NOT involved, KE + PE = ME

**Kinetic energy and potential energy change throughout a system, but the total

mechanical energy does NOT change.