Force Pairs & Systems (Newton's Third Law Deep Dive) - Study Guide

REF STUDY GUIDE: Big Ideas Use to answer form questions

1.Newton's Third Law: Every force has an equal and opposite partner — when you push on a desk, the desk pushes back on you with exactly the same amount of force in the opposite direction.

2.Why Force Pairs Don't Cancel: Action-reaction forces act on two different objects, not the same one — your foot pushes the ground backward and the ground pushes you forward, so you accelerate even though the forces are equal in size.

3.Equal Forces, Different Accelerations: When two objects push on each other with equal force, the lighter object accelerates more because a = F/m — a skateboard rolls away faster than the person who pushed it.

4.Biological Force Pairs: Animals move by pushing against their environment — a fish pushes water backward with its tail and the water pushes the fish forward, which is Newton's Third Law in living systems.

DRAW KEY TERMS Google each → Images tab → sketch what you see

Newton's third law

For every action, there is an equal and opposite reaction

System

The objects we are analyzing in a situation

force pair

Two equal and opposite forces acting on different objects

action-reaction

Newton's Third Law: every force has an equal opposite partner

WRITE FOCUS QUESTION Your initial thinking

Every time you take a step, jump, or even just stand still, Earth's gravity pulls you downward. But Newton's Third Law says forces always come in pairs — so is there a force pulling back on Earth too?

If Earth pulls you with gravity, do you pull Earth?

I think...TODO: author answer text

WRITE AFTER HOOK FORM Reflect before continuing

I learned that... TODO: author answer text

Station 1 — Force Pair Identification

I observed that... TODO: author answer text

This shows that... TODO: author answer text

The key concept is... TODO: author answer text

Station 2 — Biological Force Pairs ⭐ CRITICAL FOR C3

The data shows... TODO: author answer text

This connects to... TODO: author answer text

The main idea is... TODO: author answer text

This connects to what we learned because...

I can apply this by... TODO: author answer text

DRAW CONCEPT MODEL Show your understanding visually

Draw a model that shows the main concept. Include labels and arrows to explain relationships.

TODO: author answer text

Labels included

Relationships shown

Key terms used

CHECK TEST YOUR THINKING Rate each: FALSE ← 1-2-3-4-5 → TRUE

1. When you push a wall, the wall does not push back on you.

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2. Action-reaction forces are equal and opposite, so they always cancel each other out.

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3. If two forces are equal and opposite, neither object can accelerate.

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4. The bigger or stronger object in a collision exerts more force than the smaller one.

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5. When a bug hits a car windshield, the car exerts a greater force on the bug than the bug exerts on the car.

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Pick any TWO statements — especially any you rated 2, 3, or 4. Justify your rating with evidence:

Statement #___ — I rated it ___ because:

THINK SCIENTIST CIRCLE DEBRIEF Reflect after your Scientist Circle discussion

AHA! Moment

The one I changed my thinking most about is... TODO: author answer text

Remaining Question

I still wonder... TODO: author answer text

WRITE FOCUS QUESTION REVISIT Final written response

If Earth pulls you with gravity, do you pull Earth?

TODO: author answer text