Conservation of energy and power Flashcards
1
Q
What is the conservation of energy?
A
- Energy is transferred, stored or dissipated
- Not created or destroyed
2
Q
What is dissipated energy known as?
A
- Wasted energy
3
Q
Describe energy transfers for a closed system.
A
- Cold spoon dropped into hot soup
- Soup flask is thermal insulator –> spoon + soup = closed system
- Energy transferred from thermal store of soup to spoon (soup cools down a little)
- Energy transferred but no energy has left (net change: zero)
4
Q
Formulae for power:
A
P = E/t
P = W/t
- Energy transferred = Work done
5
Q
What is a powerful machine?
A
- Exerts strong force over a short time