Untitled Lesson

TEKS 7.7D, 7.1A, 7.2A

Newton’s First Law
of Motion

KEY IDEAS

• What is Newton’s first law of motion?
• How do unbalanced forces affect motion?
• How do balanced forces affect motion?

Words to Know

force
inertia

unbalanced forces

balanced forces

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Copyright © Savvas Learning Company LLC. All Rights Reserved. Savvas is not responsible for any modifications made by end users to the content posted in its original format.

What is Newton’s First Law of Motion?

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What is Newton’s First Law of Motion?

continued

A force is a push or a
pull. An object will stay
at rest or in uniform
motion unless acted
upon by an unbalanced
force. That tendency is
called inertia. Newton’s
first law of motion
states that an object
will maintain its state of
motion unless a force
acts upon it.

Photo credit: Ruth Jenkinson/Dorling Kindersley ltd/Alamy Stock Photo

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Poll: Newton’s First Law

Analyze Which of these two statements is correct?

Newton’s First Law of Motion
is really two laws, because
putting a stationary body
into motion is different
from changing the motion
of a moving object.

Newton’s first law is a
statement that applies
to any kind of motion

#

#

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How do unbalanced forces affect motion?

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How do unbalanced forces affect motion?

continued

Unbalanced forces
can move an object or
change the motion of
an object that is
already moving. The
more speed a moving
object has, the more
force is required to
change its motion.

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Describe the forces’ effects

SEP Identify Enter the correct term in each blank.

Word bank

produces

speeds up

slows down

velocity

Gravity

the downward motion

of a skydiver who has jumped from a plane.

Magnetism

the upward motion

of iron filings toward a magnet held above them.

Friction

the rotation of a bicycle

wheel.

A swinging baseball bat changes the

of a pitched ball.

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Describe the forces’ effects Answers

SEP Identify Enter the correct term in each blank.

Word bank
Gravity

speeds up

the downward motion

of a skydiver who has jumped from a plane.

Magnetism produces

the upward motion

of iron filings toward a magnet held above them.

Friction slows down

the rotation of a bicycle

wheel.

A swinging baseball bat changes the velocity

of a pitched ball.

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How do balanced forces affect motion?

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How do balanced forces affect motion? continued

Balanced forces produce a net force of zero if they
are acting on the same object. When an object is at
rest, the downward force of gravity is balanced by
other, upward forces.

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Identify the opposing forces

SEP Identify Enter the correct words in the blank columns of the table.

Word bank

friction

upward

downward

gravity

pressure

to the left

Action
Force from

Hand

Opposing

Force

Photo credits: Jessica Borbon/Shutterstock; Alistair Berg/Photodisc/Getty Images; Andrey_Popov/Shutterstock

Copyright © Savvas Learning Company LLC. All Rights Reserved. Savvas is not responsible for any modifications made by end users to the content posted in its original format.

Identify the opposing forces Answers

SEP Identify Enter the correct words in the blank columns in the table.

Word bank
Action
Force from

Hand

upward

to the left

downward

Opposing

Force

gravity

friction

pressure

•Photo credits: Jessica Borbon/Shutterstock; Alistair Berg/Photodisc/Getty Images; Andrey_Popov/Shutterstock

Exit Ticket

Choose one of the following ways to
analyze and explain how balanced and
unbalanced forces affect the motion of
objects.

1.

Draw a scenario in which the forces
acting on an object change from
balanced to unbalanced and label
what happens.

2.

Write a short narrative that describes
what causes an object to gain or lose
speed due to a change in the balance
of forces acting on that object.