Every Arrow Needs an Employer

You'll learnto draw a free-body diagram where every force arrow names a real source.

A free-body diagram is a payroll list: each force arrow works for somebody you can point to — Earth, a surface, a rope, a hand. Watch the diagrams build themselves, catch the phantom arrow students love to draw, then run one from diagram to acceleration.

8 STEPS · 6 QUICK CHECKS · g = 10 m/s² · v5

Before you start

What you're looking at

A ball rising after being tossed, beside an empty free-body diagram waiting to be filled with force arrows.

The question

Which arrows really belong on the diagram, and which phantom force do students wrongly add?

Watch for

Test each proposed arrow by asking who pushes or pulls; only forces with a real source survive.

What the symbols mean

Each arrow color marks its source: Earth (gravity), a surface (normal, friction), a rope (tension), a hand (applied).

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