Unit 15 Lesson 4 What Are Newton’s Laws? · 15/01/2019 · Unit 15 Lesson 4 What Are Newton’s...

Unit 15 Lesson 4 What Are Newton’s Laws?

Copyright © Houghton Mifflin Harcourt Publishing Company


Newton’s First Law of Motion


• In the 1600s, Isaac Newton published a book about how objects move in the physical world.

• Newton summed up his ideas in three rules, or laws.




• Newton’s first law describes inertia, or the tendency of objects to resist a change in motion.

• For example, when a car makes a sudden turn, your body pulls to the other side of the car.

http://www-k6.thinkcentral.com/content/hsp/science/fusion/common/glossary_9780547511795_/html/grade.html?grade=gr05?language=en?term=brain

15.4 videos/Eureka! Program 1 - Inertia.mp4




• Newton’s first law of motion states that no acceleration, or change in motion, can happen without an unbalanced force, or push or pull.

• In other words, objects at rest don’t move unless an unbalanced force acts on them.

• Objects in motion don’t slow down, speed up, stop, or turn unless a force makes them do so.


Newton’s Second Law of Motion


• Newton’s second law of motion states that an object’s acceleration depends on two factors: the amount of force applied to the object and its mass.

15.4 videos/eureka 4 acceleration I.mp4




• The mass of an object affects how, or if, the object moves when a force is applied to it.

• Newton’s second law explains why you must use more force to move an object with a greater mass.

• This law can be written as an equation:

Force = mass x acceleration

15.4 videos/eureka 5 acceleration II.mp4


Newton’s Third Law of Motion


• Newton’s third law of motion states that whenever one object applies force to another, the second object applies an equal, opposite force to the first object.

• In other words, this law says that forces always act in pairs.

15.4 videos/Newton's 3 (three) Laws of Motion.mp4




• Sometimes scientists use the terms action force and reaction force to refer to a pair of forces.

• In other words, the two forces described above are equal in size and opposite in direction.

• For example, when leaning against a wall, your body applies force to the wall. The wall doesn’t move because it applies the same amount of force to you.


Motion in Space


• Astronauts in orbit appear to be weightless.

• To understand motion of objects in space, it’s important to remember the difference between weight and mass.

• Mass refers to how much matter is in an object. Weight refers to how much force is applied to an object by gravity.

15.4 videos/eureka 7 weight VS mass.mp4


Motion in Space


• Newton’s laws of motion apply to objects in space, because the laws involve mass, not weight.

• The mass of an object is the same on Earth and in space.

• An object’s weight can change because weight is related to the force of gravity at a particular location.


Motion in Space


• Astronauts feel and look weightless because of microgravity.

• Microgravity occurs because Earth’s gravity causes the space station to fall toward Earth at a constant rate. Everything inside the space station falls at the same rate.

15.4 videos/What is Microgravity_.mp4


Motion in Space



Motion in Space


• Because astronauts are also in free fall, they appear to float.


Motion in Space


Unit 15 Lesson 4 What Are Newton’s Laws? · 15/01/2019 · Unit 15 Lesson 4 What Are Newton’s...

Documents

Transcript of Unit 15 Lesson 4 What Are Newton’s Laws? · 15/01/2019 · Unit 15 Lesson 4 What Are Newton’s...