Newton's

First Law of Motion

"Every object continues in a state of rest, or of motion in a straight line at constant speed, unless it is compelled to change that state by forces exerted upon it"

 

In other words, all objects want to "keep on doing what they're doing" . The only thing that stops them from continuing to do "what they were doing" is an unbalanced force.

Here are some other examples:

An object at rest will remain at rest unless an unbalanced force does something to it.

1. I filled a cup with water.

2. I placed a card on top of the cup.

3. I put a penny on top of the card.

4. I used my index finger and thumb to flick the card away.

What do you think happened to the penny?

Watch the movie to find out.

Check your understanding:

1. What was the unbalanced force?

2. Which object received the unbalanced force, the penny or the index card?

3. Why didn't the penny fly off with the index card?    


4. What force made the penny drop into the cup of water?

An object will continue to move in a straight line at a constant speed unless an unbalanced force does something to it.

1. I built an inclined planed.

2. I placed a toy car and a passenger at the top of the inclined plane.

3. I let go of the car and allowed it to accelerate down the inclined plane.

4. I placed a book at the bottom of the inclined plane.

What do you think happened to the figure in the toy car?

Watch the movie to find out.

Toy Car Crash

Check your understanding:

1. When the car stopped what happened to the passenger?

2. What force stopped the car?  


3. Why did the passenger continue to move in a straight line?

4. What force(s) finally stopped the passenger?

 

http://www.usoe.k12.ut.us/curr/science/sciber00/8th/forces/sciber/newtons.htm

l http://www.physicsclassroom.com/Class/newtlaws/U2L1a.html

 

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