Raven spreads a printed page across the picnic table. "NASA keeps a review table of all three laws. Here it is."
Rocket reads the first row aloud. "An object at rest remains at rest. We saw that with the ball in week 2."
"Second row," Raven says. "Acceleration depends on mass and force. That was the two balls on the ramp."
Rocket taps the third row. "Equal and opposite. The balloon, the jump, the swimmer. That is this week."
Nova hovers over the page, her glow steady. "What do you notice about how the three fit together?"
"They are all about forces changing motion," Rocket says slowly. "The third one just says where forces come from."
Raven smiles. "Then you are ready to read it like a scientist."
NASA Glenn Research Center publishes a Beginner's Guide to Aeronautics with a review table of Newton's laws. Here are its three rows.
Read each row and match it to something you did at the Field this term.
| Law | What it says (NASA's words) | Field moment |
|---|---|---|
| First law (inertia) | An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force. | Week 2: the rolling ball kept rolling until friction stopped it |
| Second law (force) | The acceleration of an object depends on the mass of the object and the amount of force applied. | Week 3: the same push moved the light ball more |
| Third law (action and reaction) | Whenever one object exerts a force on another object, the second object exerts an equal and opposite force on the first. | Week 9: the balloon pushed air back and the air pushed it forward |
The same NASA page lists three examples of action and reaction in flight. Each one is a pair of forces.
A wing deflects air downward, and in reaction the wing is pushed upward. That is lift.
A spinning ball deflects air to one side, and the ball reacts by moving in the opposite direction. That is why some kicks curve.
A jet engine pushes hot exhaust gas out the back, and a thrusting force is produced in the opposite direction.
Every example has the same shape: push something one way, get pushed the other way.
| Statement | True or false? |
|---|---|
| The first law says motion stays the same unless an unbalanced force acts. | ? |
| The second law says acceleration depends on mass and force. | ? |
| The third law says the reaction force is smaller than the action force. | ? |
| A spinning ball curves because the air pushes it to one side. | ? |
Excellent data reading. Tomorrow you take the third law to the pitch, the pool and the track.