According to Newton's First Law, what will an object at rest do?

Remain at rest unless acted on by an unbalanced force

Explain, in your own words, what is meant by the term 'inertia' and how it relates to Newton's First Law.

Inertia is the tendency of an object to resist changes in its state of motion. Newton's First Law, also known as the Law of Inertia, describes this tendency: objects at rest stay at rest, and objects in motion stay in motion with the same velocity unless acted upon by an unbalanced force.

Describe a scenario where an object is in motion but eventually comes to a stop. Explain what forces are acting on the object to cause it to stop, relating your answer to Newton's First Law.

A ball rolling on the ground will eventually stop due to forces like friction and air resistance. These unbalanced forces act against the motion of the ball, causing it to slow down and stop, which is why it doesn't continue moving indefinitely as Newton's First Law suggests it would in the absence of such forces.

Imagine you are in a spaceship far from any stars or planets. You throw a ball. What does Newton's First Law predict will happen to the ball?

Newton's First Law predicts that the ball will continue moving in a straight line at a constant speed forever, since there are no significant external forces (like gravity or air resistance) to act upon it.

Why is it more difficult to start pushing a heavy box from rest than to keep it moving once it's already sliding?

It is more difficult to start pushing a heavy box from rest because you must overcome its inertia, the tendency to resist changes in its state of motion. Once the box is moving, you only need to apply enough force to overcome friction and maintain its constant velocity, as described by Newton's First Law.

Newton's First Law of Motion

7th GradeScience40 min

aligned to Ngss Ms-ps2-2

Learning Objective

I can explain how Newton's First Law applies to objects at rest and in motion.

Lesson Flow

Watch Video

10 min

More on Newton's first law of motion | Physics | Khan Academy

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Guided Notes

8 min

Key concepts students will learn:

•
Newton's First Law states that an object will stay at rest or move with a constant velocity unless acted upon by an unbalanced force.
•
An unbalanced force is required to change an object's state of motion; if forces are balanced, the object's motion remains unchanged.
•
In real-world scenarios, objects in motion tend to stop due to unbalanced forces like friction and air resistance, which counteract the motion.

Practice

12 min

5 questions • Multiple choice & Short answer

Exit Ticket

5 min

“Explain how Newton's First Law applies to a soccer ball sitting on the ground and a hockey puck sliding across the ice.”

Teacher Guide

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Answer keys for all questions
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Newton's First Law of Motion

Learning Objective

Lesson Flow

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Guided Notes

Practice

Exit Ticket

Teacher Guide

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