Energy Transfers/Transformations
What is an energy transfer?
When energy is transferred to another object but remains the same type of energy. Example: kinetic energy --> kinetic energy
What is the equation for PE?
PE = mgh
What is a criteria?
A want
What is work?
When something is moving
What is energy transformation?
When energy changes from one type to another type of energy. Example: Potential energy changes to kinetic energy.
What is the equation for KE?
KE = 1/2mv2
What is a constraint?
A must
What is the equation for work?
W = Fd
A person pushes a stack of books.
1) Is there a transfer of energy?
2) Is work done?
1) Yes
2) Yes
What number is always used for "g" in the PE equation?
9.8
What should come first in the design process:
Stating the design problem
OR
Making a list of constraints?
Stating the design problem
What do you need to measure the PE of a rubber band?
Height and mass. Gravity is always 9.8
In our rollback cans, describe one energy transfer that took place.
Our kinetic energy transferred into kinetic energy in the can to get it rolling
A stack of books weighs 8 grams and is sitting on a table 5 meters high. Find the PE.
392 J
Do you test your prototype only one time?
No. You test and retest and redesign until you come up with the best possible design that meets as many criteria and all constraints given
Where is potential energy in a roller coaster the highest?
At the top of the highest hill
Describe one energy transformation that took place in our rollback cans.
The kinetic energy was transformed into potential energy or elastic potential energy as the rubber band wound up as the can rolled
A ball has a mass of 6 grams and is traveling at a velocity of 3 meters per second. Find the KE.
27 Joules
What is the key word to look for when talking
a) criteria?
b) constraints?
a) should
b) must
Where is kinetic energy the highest for a roller coaster?
At the bottom of the highest hill