Unit 7: Energy. Bell Ringer. HAND IN FOLDABLE

What is the Law of Conservation of mass? Give

an example

What are four signs of a chemical change?

Note to self: RETAKES

Unit 7: Energy.

Energy: the ability to do work

When an object does work on another, energy is transferred

Unit 7: Energy.

Units for energy are Joules!

Unit 7: Energy.

Two types of energy…. - Kinetic energy: energy of motion - Potential energy: of position or shape

Unit 7: Energy.

Kinetic energy = mv2

2

Unit 7: Energy.

The red car has more KE than the green car because the red car is moving faster

Let’s Try: What is the KE of the 2,000 kg red car?

What is the KE of the 2,000 kg green car?

Unit 7: Energy.

The truck has more KE than the red car because the truck is more massive!

Let’s Try: What is the KE of the 10,000 kg truck?

Unit 7: Energy.

Potential energy = weight x height

Sometimes PE is referred to as “Gravitational Potential Energy”! Same

Thing

Unit 7: Energy.

Height and weight affect PE

Circle who has greater PE for each

Unit 7: Energy.

Let’s Try: If you lift a 50N watermelon to the top of a 2 m refrigerator, how much PE do you give

the watermelon?

Unit 7: Energy.

Putting it all together

Where does the pendulum have the greatest

PE?

Where does the pendulum have the greatest

KE?

Unit 7: Energy. Mechanical energy: the total energy of

motion and position of an object.

ME can be all PE, all KE, or some of both!

Unit 7: Energy.

ME = PE + KE

Mr. Edmond Song https://www.youtube.com/watch?v=_uLSFigtLKg

Unit 7: Energy.

Physics Coaster!

Unit 7: Energy. TAKE OUT PE KE HW

Bell Ringer: You are on a roller coaster 92 meters above the ground traveling at 14 m/s. You weigh 400

N (or approximately 40.8 kg). What is your mechanical energy? Show your work and include

your units!