Newton Laws Practice Worksheet
Newton’s Laws of Motion Notes and Practice
Name:
Date:
Period:
Know and Show
| I need to KNOW | I will SHOW my learning by… |
|---|
| A force is a push or pull. | Identifying forces in everyday situations. |
| Newton’s First Law explains inertia. | Explaining why an object’s motion resists change. |
| Newton’s Second Law is \( F = ma \). | Calculating force, mass, or acceleration. |
| Newton’s Third Law describes force pairs. | Identifying equal and opposite forces acting on different objects. |
| Balanced forces produce a net force of 0 N. | Comparing balanced and unbalanced forces. |
Chunk 1: Newton’s First Law
Newton’s First Law is also called the Law of Inertia.
Inertia is the resistance of an object’s motion to change.
- An object at rest remains at rest unless an unbalanced force acts on it.
- A moving object continues moving at the same speed and in the same direction unless an unbalanced force acts on it.
- Inertia is a property of matter. It is not a force.
- Objects with more mass have more inertia.
Examples:
- A book remains on a desk until someone moves it.
- A soccer ball remains still until a player kicks it.
- A passenger continues moving forward when a car suddenly stops.
- A seat belt applies a force that stops the passenger safely.
Quick check: Newton’s First Law explains .
Chunk 2: Newton’s Second Law
Newton’s Second Law explains the relationship among force, mass, and acceleration: \( F = ma \)
- \( F = \) force measured in newtons (N)
- \( m = \) mass measured in kilograms (kg)
- \( a = \) acceleration measured in meters per second squared (m/s²)
Important relationships:
- More force produces more acceleration when mass stays the same.
- More mass produces less acceleration when force stays the same.
- Acceleration occurs in the direction of the net force.
Example: A 3 kg cart is pushed with a force of 12 N.
\( a = \frac{F}{m} = \frac{12\text{ N}}{3\text{ kg}} = 4\text{ m/s}^2 \)
Quick check: If force increases while mass stays the same, acceleration .
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Chunk 3: Newton’s Third Law
Newton’s Third Law states that when one object applies a force to another object, the second object applies an equal force in the opposite direction.
Third Law forces:
- Are equal in size.
- Point in opposite directions.
- Act on two different objects.
- Occur at the same time.
Examples:
- A swimmer pushes water backward; the water pushes the swimmer forward.
- A balloon pushes air backward; the air pushes the balloon forward.
- A student pushes down on the ground; the ground pushes the student upward.
- A tire pushes backward on the road; the road pushes the tire forward.
Sentence pattern: Object A pushes Object B; Object B pushes Object A in the opposite direction.
Quick check: Third Law forces do not cancel because they act on .
Balanced and Unbalanced Forces
Balanced forces
- Have a net force of 0 N.
- Do not change an object’s motion.
- Can act on an object that is resting or moving at a constant velocity.
Unbalanced forces
- Have a net force other than 0 N.
- Cause acceleration.
- Can make an object start, stop, speed up, slow down, or change direction.
Questions: Selected Response
1. Which statement describes Newton’s First Law?
A. Force equals mass times acceleration. B. An object’s motion remains unchanged unless an unbalanced force acts. C. Every force has an equal force acting on the same object. D. Heavier objects always move faster.
Answer:
2. What is inertia?
A. The speed of an object B. A force that stops motion C. Resistance to a change in motion D. The direction of a force
Answer:
3. A 4 kg object accelerates at 3 m/s². What force acts on it?
A. 1 N B. 7 N C. 12 N D. 24 N
Answer:
4. A swimmer pushes water backward. What is the reaction force?
A. Gravity pulls the swimmer downward. B. The water pushes the swimmer forward. C. The swimmer stops moving. D. Friction pushes the water backward.
Answer:
5. Two students push a box with 10 N in opposite directions. What is the net force?
A. 0 N B. 10 N C. 20 N D. 100 N
Answer:
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Questions: Short Responses
Provide complete explanations using the provided sentence stems and handwriting lines.
6. Explain why a passenger needs a seat belt when a car suddenly stops.
Sentence stem: The passenger needs a seat belt because the passenger’s body continues due to . The seat belt applies that changes the passenger’s motion.
7. Explain how increasing force affects acceleration when mass remains constant.
Sentence stem: When force increases and mass remains constant, acceleration because .
8. Explain how increasing mass affects acceleration when force remains constant.
Sentence stem: When mass increases and force remains constant, acceleration because .
9. Identify the action-reaction forces when a student jumps.
Sentence stem: The student pushes , and pushes the student .
10. Compare balanced and unbalanced forces.
Sentence stem: Balanced forces have a net force of and cause . Unbalanced forces have a net force of and cause .
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Student Self-Check
Check each statement that describes your understanding.
I can define force. I can identify a Third Law force pair. I can explain inertia. I know that Third Law forces act on different objects. I can state Newton’s First Law. I can distinguish balanced from unbalanced forces. I can use \( F = ma \). I included units in my calculations. I can identify force, mass, and acceleration in a problem. I reviewed my answers.
Fist-to-Five: Circle your current level of understanding.
0 1 2 3 4 5
What I Know and Need
What I know: I know that Newton’s laws because .
Assistance needed: I still need assistance with . One question I have is .
Cut or Perforate Here
Exit Ticket
Hand in upon completion
A 5 kg cart is pushed with a net force of 20 N.
1. Calculate the cart’s acceleration. Show your work.
\( a = \frac{F}{m} = \)
= m/s²
2. Explain what the answer means.
Sentence stem: The cart accelerates at because a net force of acts on a mass of .
3. Which Newton’s law did you use?
Sentence stem: I used Newton’s Law because .
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