Newton’s Three Laws

Egg Number/Name

     Time of Fall (s)

         

 Group

1Group

2Group

3Group

4Group

5Group

6Group

7Group

8avg

                                                                                                                                     

               

IQ 12/16/13page 70

• Why does a bowling ball eventually stop when you throw it down the lane? Explain using scientific terms.

Athletes use spinning, pushing and bumping motions to score points.

• Can you think of some examples?

Newton’s First Law of Motion

• An object at rest remains at rest unless acted on by an unbalanced force.

• An object in motion continues in motion with the same speed and direction unless acted upon by an unbalanced force.

• This law is often called “the law of inertia".

What does inertia mean?

• Objects tend to keep on doing what they're doing. • Inertia depends on the mass of the object. • The more massive the object, the more it resists

changes in its motion.

Real World Examples…

• Soccer

If I kick a soccer ball towards the net and the goalie is not there to stop it…

GOAL!!!

• Bowling

When I roll the bowling ball down the lane, it will keep going until it hits the pins… or the gutter!

How can I describe a “magic trick” in terms of forces?

• Materials:• Cup• Playing card• Coin

• Create a hypothesis:

1) Suppose you were to flick the card, sending it flying horizontally. What would happen to the coin? Why?

2) Suppose you were to slowly pull the card horizontally from the mouth of the cup. What would happen to the coin? Why?

Conclusions:

3) Which forces acted on the coin before the card moved?

4) Which forces acted on the card as it moved?

5) Using Newton’s Laws of Motion, explain what happened to the coin when the card was flicked.

• Conclusions:• 3) Which forces acted on the coin before the

card moved?• 4) Which forces acted on the card as it

moved?• 5) Using Newton’s Laws of Motion, explain

what happened to the coin when the card was flicked.

•

How do magicians perform the tablecloth trick?

IQ 12/17/13pg 72

• Would it take more force to push a car or a bike? Why? Explain

Newton’s Second Law of Motion

• Acceleration (change in speed or direction) is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

Which situation would require most force?

• Heavy shopping cart vs. empty shopping cart• Stopping a person on a bike vs. catching a

basketball• Kicking a tennis ball and kicking a bowling ball• Pushing a 40 kg box vs. pushing a 1 kg box

• More mass-more force to move object

• Less mass-less force to move object

What does the 2nd law mean?

• Heavier objects require more force to move the same distance as lighter objects.

•

Real World Examples

• If you are a defensive lineman, who would be easier to tackle…

A running back that weighs 100 pounds or a running back that weighs 300 pounds?

IQ 12/18/13pg74

• Which one of Newton’s Laws is the relationship between amount of force needed to accelerate an object’s mass?

Newton’s Third Law of Motion

• For every action there is an equal and opposite re-action.

• If one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object.

• Action and reaction forces in a pair do not act on the same object, otherwise nothing would move.

Equal but OppositeEqual but Opposite

What does this mean?

This means that for every force there is a reaction force that is equal in size, but opposite in direction. That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard.

In the Real World…

• Golf

When Tiger Woods hits the golf ball…what is the reaction?

• Racing

• When Dale Earnhardt steps on the gas pedal, what is the reaction?

Ex. swimming

Ex. Running

Your Task – Choose one of the following:

• Write a paragraph to explain an example of each of Newton’s 3 Laws

• OR, Draw a picture to illustrate each of Newton’s 3 Laws

• Now that I’ve given you a few examples, I want you to think of one example of each of Newton’s Three Laws of Motion from sports.

Conservation of Momentum