Mechanical Energy – Potential and Kinetic energy Unit Objectives: I can identify the different energy forms and explain the transfers of energy involved in the operation of common devices. By the end of today: I will be able to describe the difference between potential and kinetic energy.

WARM UP: When does the bowling ball have the most potential energy? When does the bowling ball have the most kinetic energy? A bowling ball is initially at rest at the top of a hill. Then the ball rolls down the hill.

Mechanical energy – 2 types Kinetic Potential

The energy stored due to position (when something is NOT moving) Potential energy The energy stored due to position (when something is NOT moving) Two Types!

Which situation is an example of potential energy? pulling a wagon uphill emptying a bucket of water a cat jumping from a tree a bicyclist stopped at a stop sign Your keyword is “stopped.” An object has potential energy (stored energy) when it is not moving.

Gravitational potential energy Def: The stored energy of elevated objects (gravitational potential energy is synonymous with potential energy) example: you standing still on Earth A book sitting on a table A boulder at the edge of a cliff

Elastic potential energy Def: The energy stored in a deformable (squishy or stretchy) object examples of a deformable object: a spring, squishy ball, slinky, rubber band

Kinetic energy - MOTION The energy of a moving object.

When does a toy race car have kinetic energy? rolling down a hill sitting on a shelf upside down on the floor in the toybox with the lid closed Your keyword is “rolling.” An object has kinetic energy (energy of motion) when it is moving.

Which of the following is an example of kinetic energy? a child jumping rope a swimmer ready to dive a stuffed toy lying on a table firewood stacked in a fireplace

A car stopped at the top of a ramp has heat energy. potential energy. kinetic energy. mechanical energy.

Emily is riding a roller coaster, which moves up a hill slowly and then starts to move faster as it goes towards the bottom of the hill. Where on the hill will Emily have the MOST kinetic energy ? Halfway up the hill. At the top of the hill. Halfway down the hill. At the bottom of the hill.

When a pitcher throws a baseball, which of these has MOSTLY kinetic energy? the pitcher the ball the batter the catcher

Which of these best shows kinetic energy?

At which point on the track does the train have the most PE? KE? Position 1 has the most PE. Position 3 has the most KE.

Comprehension Check! When does the bowling ball have the most potential energy? When does the bowling ball have the most kinetic energy? A bowling ball is initially at rest at the top of a hill. Then the ball rolls down the hill.

EXIT TICKET: Describe one moment that you experienced kinetic energy today. Describe one moment that you experienced potential energy today.