Chapter 10, Lesson 4

Open Ended

Tell me everything you know about Newton's Laws of Motion.

newton's Laws of Motion

Chapter 10, Lesson 4​

Pages 386-393

Newton's First Law of Motion

Newton's first law of motion states than object at rest will remain at rest and an object in motion will remain in motion unless acted on by an unbalanced force.

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Inertia - is the resistance to change in motion

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Newton's First Law of Motion

The greater the mass of an object, the greater its inertia, and the greater the force required to change its motion

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Inertia can explain a lot of things, including why you are thrown forward in your car seat when the driver slams on the brakes.​

Newton's Second Law of Motion

Newton's second law of motion states that an object's acceleration depends on its mass and on the net force acting on it

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This can be written as an equation

Force = mass * acceleration

OR acceleration = force / mass

OR mass = force / acceleration​

Newton's Second Law of Motion

A shopping cart is easier to push if it is empty. Once it is full it has more mass than before.

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An adult will cause more acceleration on a shopping cart than a child​

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If you continue to push with the same force but an object falls off of your shopping cart, you will now have a greater acceleration​

Open Ended

Suppose that four dogs pull a sled carrying two people. How could you increase the sled's acceleration?

Open Ended

Suppose that four dogs pull a sled carrying two people. How could you decrease the sled's acceleration?

Open Ended

What equation allows you to calculate the force acting on an object?

Multiple Choice

What is the net force on a 2kg skateboard accelerating at a rate of 2 m/s²?

• 4

• 1

• 0

• 2

Open Ended

If the mass of the skateboard doubled but the net force on it remained constant, what would happen to the acceleration of the skateboard?

Newton's Third Law of Motion

Newton's third law of motion states that for every action, there is an equal but opposite reaction​

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When you walk, your foot pushes on the ground (action) and the ground pushes back up on your foot (reaction)​

Newton's Third Law of Motion

Newton's third law can also explain why rockets accelerate in space. The gas that is produced and pushed backward out of rockets (action) the rocket is propelled forward (reaction)

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Action/reaction forces do not cancel like balanced forces because they act on different objects - A swimmer exerts a backward action force on water and the water exerts an equal but forward action force on her hands​

Open Ended

A dog pulls on his leash with a 10N force to the left but doesn't move. Identify the reaction force.

Multiple Select

What is the equation that describes the relationship between force, mass, and acceleration? (select all that apply)

• F=ma

• m=fa

• m=f/a

• a=f/m

Multiple Choice

If you increase the force on an object, its acceleration increases.

• True

• False

Multiple Choice

If you increase the mass of an object, its acceleration decreases.

• True

• False

Multiple Choice

To accelerate a 3kg skateboard at 9m/s², a force of 3N is needed.

• True

• False

Multiple Choice

The amount of inertia an object has depends on its speed.

• True

• False

Multiple Choice

Newton's first law of motion states that an object will not experience a change in motion unless acted upon by a balanced force.

• True

• False

Multiple Choice

To increase acceleration of an object, you reduce its mass or increase the applied force.

• True

• False

Multiple Choice

Newton's third law of motion states that if one object exerts a force on another object, then the second object exerts a force of equal strength in the same direction.

• True

• False

Multiple Choice

Resistance to change in motion is called stasis.

• True

• False

Multiple Choice

Action and reaction forces acting in opposite directions do cancel out because they act on different objects.

• True

• False

Multiple Choice

If you lean against a wall, the wall pushes back on you with a weaker force.

• True

• False