Newton's Laws Review

Newton's Laws Review

​Newton's 1st Law

​Objects maintain their same state of motion - AT REST or MOVING AT A CONSTANT VELOCITY - unless acted on by an unbalanced force.

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Unbalanced forces result in an ACCELERATION.

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​Also known as the Law of INTERTIA

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​Newton's 1st Law

​Inertia is related directly to an object's mass. The more mass, the more inertia.

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​The more inertia, the more the object wants to maintain it's current state of motion - AT REST or MOVING AT A CONSTANT VELOCITY

​Finding net force

​Add (and subtract) forces in the horizontal.

​Add (and subtract) forces in the vertical.

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​Do you get a net force of 0 N? No acceleration.

​Do you get a net force of anything other than 0 N? ACCELERATION!

Poll

Which of these force diagrams show balanced forces? Pick all that apply

• Diagram Q

• Diagram R

• Diagram T

• None

Poll

Which of these force diagrams show an object accelerating? Select all that apply

• Diagram Q

• Diagram R

• Diagram T

• None

Poll

Which of these force diagrams could show an object at rest? Choose all that apply

• Diagram Q

• Diagram R

• Diagram T

• None

Poll

Which of these force diagrams could show an object moving to the right at a constant velocity? Choose all that apply

• Diagram Q

• Diagram R

• Diagram T

• None

Multiple Choice

What is the net force?

• 17 N Right
• 3 N Right
• 3 N Left
• 17 N Left

​Newton's 2nd Law

​F = ma

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​If a certain amount of force is applied to a small mass, that mass will experience a large acceleration.

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​If that same amount of force is applied to a larger mass, that mass will experience a small acceleration.

Multiple Choice

If the man pushes with an equal amount of force, which object will accelerate more?

• Car because it has more mass

• Lawnmower because it has less mass

• Car because it has less mass

• Lawnmower because it has more mass

Multiple Choice

A force of 90N is applied to each cart below, which one will accelerate the fastest?

• Cart 1
• Cart 2
• Cart 3 
• Cart 4

​Newton's 3rd Law

​For every force there is an equal and opposite force.

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​Equal in MAGNITUDE (how many Newtons of force)

​Opposite in DIRECTION

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​ALL forces come in pairs. The forces don't cancel out because they are acting on DIFFERENT objects!

​In this example, the swimmer would be accelerated forward by the equal force because her mass is smaller than the wall (F= ma)

Multiple Choice

Two people are skateboarding. If person 1 has a larger mass than person 2 and person 1 pushes person 2, how much would this affect their movement?

• Mass will have no affect.

• They will accelerate backwards the same.

• Person 1 will accelerate more, but both will move.

• They will both accelerate back, but person 2 will move more.

Multiple Choice

A semi truck and a Volkswagen (small car) traveling at the same speed have a head on collision. Which statement is correct?

• The impact force is greater on the Volkswagen.

• The impact force is greater on the semi truck.

• The impact force is less on the semi truck.

• The impact force is equal for both.