🧭 Plot Summary
In Activity 4-1-1 you saw that lifting an object takes work. In 4-1-2 you saw that moving objects carry energy. Now the two meet: the work you do lifting something doesn’t vanish, it’s stored in the object’s height as gravitational potential energy, ready to turn into motion the moment you let go.
You’ll measure that stored energy by lifting real masses with a spring scale, then put it to the test. You’ll reuse the ramp cart from last time and ask: of the PE it lost rolling downhill, how much showed up as KE, and where did the rest go? That missing-energy question is the heart of Project 4-1-4.
What you will do in this activity
- Lift real masses with a spring scale and discover that the work you do equals mgh.
- Calculate the stored energy of everyday objects, from an apple in a tree to a roller coaster at the top of its hill.
- Learn why the “zero level” is your choice, and why the energy released by a fall doesn’t depend on it.
- Predict how fast something is moving at the bottom of a drop, using only its height.
- Compare the PE your ramp cart lost with the KE it gained, and hunt for the energy that went missing.
Why it matters
Height is the easiest energy to control. Raise it and you add energy, lower it and you take energy out. Coasters, dams, pendulums, and emergency slides all work by trading height for speed, and this is the formula that tells you how much.
✅ Self-Check Before You Roll On
Check off each item as you get there. These are not grades — they are your own signal.