Forces & Newtons Laws Of Motion Worksheet - Free Printable

Let's go through each question on the Physics Worksheet: Forces & Newton’s Laws of Motion, analyze it, and determine the correct answer based on Newton’s Three Laws of Motion.

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Newton’s Laws Recap:

- 1st Law (Law of Inertia): An object at rest stays at rest, and an object in motion stays in motion at constant velocity unless acted upon by an unbalanced force.
- 2nd Law: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass:
$ F = ma $
- 3rd Law: For every action, there is an equal and opposite reaction. When one object exerts a force on another, the second object exerts an equal and opposite force back.

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Now, let's solve each question:

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1. The more mass an object has, the more force required to accelerate the object.
✔ This describes Newton’s 2nd Law: $ F = ma $. More mass means more force needed for the same acceleration.
👉 Answer: B. 2nd Law

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2. What goes up, eventually must go down.
This is a common saying about gravity, but it’s not a direct statement of any of Newton’s laws. While gravity (an external force) causes this, the idea that "what goes up must come down" is a consequence of gravitational acceleration, not a law itself.
However, this is not a direct expression of any specific law — it's more of a general observation.
But note: It does involve unbalanced forces (gravity), so you might think of 2nd Law, but the statement itself isn't a description of the law.
Also, it's not about inertia or action-reaction.
So, best choice is:
👉 Answer: D. None

> *Note:* This is a misconception — objects don’t “have to” come down just because they went up; if no gravity, they’d keep going. So it’s not a physics law.

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3. Eventually all objects at rest will be put into motion.
✘ False. Objects at rest stay at rest unless acted on by an unbalanced force (1st Law). This statement is incorrect — not all objects at rest will move.
So this is not a valid statement of any law.
👉 Answer: D. None

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4. The acceleration experienced by an object is proportional to the force causing the acceleration and inversely proportional to the mass of the object.
This is the exact definition of Newton’s 2nd Law: $ a = \frac{F}{m} $
👉 Answer: B. 2nd Law

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5. If two objects interact, the force exerted by one object is equal to and opposite the force exerted by the other object.
This is Newton’s 3rd Law — action-reaction pairs.
👉 Answer: C. 3rd Law

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6. An object in motion wants to keep moving in a straight line at a constant velocity.
This is a description of inertia, which is Newton’s 1st Law.
👉 Answer: A. 1st Law

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7. Objects affected by unbalanced external forces will have a change in its original state of motion.
Yes — this is exactly what the 1st Law says: unbalanced forces cause changes in motion (acceleration).
So this is a correct interpretation of the 1st Law.
👉 Answer: A. 1st Law

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8. Eventually all objects in motion will come to a rest.
✘ This is a misconception. In reality, objects only stop due to friction or air resistance — unbalanced forces. In ideal situations (no friction), objects continue moving. This contradicts the 1st Law.
So this is not a correct statement of any law.
👉 Answer: D. None

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9. You have two magnets. You place the south pole of one magnet near the north pole of the other magnet. The magnets quickly move toward each other.
This involves forces between two objects — one pulls the other, and the other pulls back. The forces are equal and opposite. This is Newton’s 3rd Law.
Even though the magnets attract, the forces are still equal and opposite.
👉 Answer: C. 3rd Law

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✔ Final Answers:

1. B
2. D
3. D
4. B
5. C
6. A
7. A
8. D
9. C

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Summary Table:

| Q# | Answer | Reason |
|----|--------|--------|
| 1 | B | 2nd Law: F = ma → more mass → more force for same acceleration |
| 2 | D | Not a law; general observation, not fundamental |
| 3 | D | False statement — objects don't automatically start moving |
| 4 | B | Directly states 2nd Law |
| 5 | C | Action-reaction pair — 3rd Law |
| 6 | A | Inertia — 1st Law |
| 7 | A | Unbalanced forces change motion — 1st Law |
| 8 | D | Misconception — ignores frictionless cases |
| 9 | C | Equal and opposite forces — 3rd Law |

Let me know if you'd like this formatted as a printable answer key!