Stored and Moving
The two forms of mechanical energy
Setting up the lab…
What this lesson covers
Why it matters
A drawn bow is perfectly still — and full of energy. A flying arrow has no stretch left — just speed. Same energy, two costumes.
Predict first
Water stored high in a dam has…
Raised, stretched, squeezed or wound = POTENTIAL (stored). Moving = KINETIC. The dam is a giant savings account.
- potential energy (stored by position) — correct
- kinetic energy
- no energy until it moves
What you do
Lift the block to store energy, roll the ball to spend it — then make both accounts exactly equal.
Check yourself
A stretched rubber band holds…
Stored by its stretched STATE — released the moment you let go.
Which has kinetic energy?
Only the moving one — wind is air in motion. (The book's energy is potential.)
A faster ball has…
Faster means more energy of motion — that's why a fast ball stings and a gentle one doesn't.
- potential energy — correct
- kinetic energy
- sound energy
- the wind — correct
- a parked truck
- a book on a shelf
- more kinetic energy — correct
- less kinetic energy
- more potential energy