Newton's First Law
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Newton's First Law-
Every object maintains the same speed and direction until it is acted upon by an outside unbalanced force
Wordy Version!
Newton's First Law-
Every object maintains the same speed and direction until it is acted upon by an outside unbalanced force
Every object maintains the same speed and direction until it is acted upon by an outside unbalanced force
Every object maintains velocity until it is acted upon by an outside unbalanced force
Every object maintains velocity until it is acted upon by an outside unbalanced force
Objects keep their velocity until an unbalanced force changes it
Objects keep their velocity until an unbalanced force changes it
Things keep doing what they're doing
Which brings us to...
velocity
Inertia
It's a property of matter... right?

...but, what does that...
mean?
Inertia
An object in motion will tend to keep that motion

An object at rest will stay at rest.

So, inertia is just the property of stuff described by Newton's first law.
...but
here's the thing
Some things have more inertia...
...than others


Which one would be harder to stop?
A bowling ball


a basketball
or...
Which one has more inertia?
Even though they are about the same size, the bowling ball has more inertia.
...and the reason is because the bowling ball has more...
Mass
Mass is just how much "stuff" and object has.
Sometimes, a good way to think of it is 'the total number of atoms in a thing'
Or, how much junk is in that trunk






Practice
Imagine we drop two cats out of a window...
One cat weighs 15 pounds, the other weighs 35 pounds.


Which one will have a harder time stopping?
Why does that happen?

Practice
Can you explain why the motercycler keeps going, even though his bike has stopped?
Explain it using the language of Newton's First Law
Which is easier to accelerate, the 10 kg dog or the 50 kg woman?

Practice
Was there someone inside the van pushing the stuff out?

Practice
Explain why it all fell out using the language of Newton's First Law
Practice
Choose 'Motion'.
Then try out your ideas about inertia by playing around with the options. We will use this tool more later.
Newton's First Law
By mrgliddon
Newton's First Law
- 427