🧭 Plot Summary
So far in this unit you’ve asked how much energy moves: how much work a force does, how much KE an object has, how much PE is stored. Now you’ll ask a new question: how fast. Two machines can move the same amount of energy, but the one that does it in half the time is working at twice the power.
On Day 1 you’ll lift the same load at three different speeds and watch the work stay put while the power changes. On Day 2 you’ll measure your own power on a flight of stairs, turn power into the kilowatt-hours on an electric bill, and size a motor for a roller coaster lift hill.
What you will do in this activity
- Lift the same load slowly, at a medium pace, and quickly, and discover that the work stays the same while the power changes.
- Calculate power in watts from mass, height, and time.
- Measure your own power by climbing a flight of stairs at two different paces.
- Convert power and time into energy, in joules and in the kilowatt-hours on an electric bill.
- Size a motor for a roller coaster lift hill, a preview of Project 4-2-3.
Why it matters
Power is what you actually buy and build. A motor is rated in watts, an electric bill is charged for watt-hours, and a coaster’s lift hill has to be strong enough to finish the climb in time. You’ll use all of it again in Project 4-2-3.
✅ Self-Check Before You Roll On
Check off each item as you get there. These are not grades — they are your own signal.