Lesson 9 of 12 · Kinematics
Lesson⭐ 30 XPFrames of Reference and Relative Velocity
Kinematics.
🎯 Your mission
Master the concept. Use it tomorrow.
⚡ The twist
Nature loves to surprise the careful watcher.
Mind = Blown
🔬 The more you look, the more nature shows you.
Make a hypothesis first
Before you start: write down what you think will happen, and why.
What You'll Learn
All velocity is measured relative to something. Walk forwards at 1 m/s along a train moving at 30 m/s and your velocity is 1 m/s relative to the carriage but 31 m/s relative to the ground. Neither number is more correct — you must state the frame.
Key Words
Tap a word to see its definition.
Steps
Read the explanation above and note the two key terms before you start.
Walk at a steady pace along a moving walkway or up a down-escalator if you can find one safely. Time yourself relative to the floor and relative to the belt, and reconcile the two figures by vector addition.
Record what actually happened, including anything that did not match what you expected.
Write a conclusion that answers the question this lesson opened with, and state your uncertainty.
Check Your Understanding
Question 1
1 of 2You walk at 1 m/s along a train moving at 30 m/s. Your velocity relative to the ground is:
Where you see this in real life
This shows up in your everyday life more than you'd think.
Stretch Challenge
Try this in real life this week.
Try one experiment in real life this week — even a tiny one.
For the dinner table
“What's the most surprising thing you learned today?”
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Frames of Reference and Relative Velocity
Master the concept. Use it tomorrow.
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