| What is Inertia? | This is the explanation of why moving a bigger object that weighs more is harder then a feather |
| Explain Inertia | Inertia is based on the mass of the object. Larger mass = larger inertia = harder to change velocity. Mass is important as the formula which explains it:
Mass=Force/Acceleration. When there is more mass, it needs more force to accelerate. It has a larger Inertia |
| What is Newton's Third law? Can you rephrase to a modern example? | This law says When two objects interact, the forces they exert on each other are equal and opposite.
Can be rephrased to
If you push something, it will push back just as hard. When you stop pushing, it also stops. |
| If forces are equal, then how does anything go anywhere? | If you pushed someone, you would feel a equal but opposite force from that same point. So would the other person, he would feel that push.
They would then both accelerate in opposite directions.
Mass also plays a roll, if the person who pushed the other person had a mass of 55kg, and the other one had a mass of 70kg, the 55kg person would be accelerated further due to the rearranged Newton's Second law
[Acceleration = Force/Mas]
The 55kg would have a smaller Inertia. |
| What about an object in equilbrium? | Imagine a book on a table. The books weight pulls it down, while the table pushed it up [normal reaction force]
This is not Newton's third law however. These forces are different types and are acting on the book together.
The pairs of forces from Newton's Third law would be:
The Book's weight by gravity, and then being pulled back up by Earth
The table normal contact force pushing up on the book, and the normal contact force from the book pushing down on the table |
