Top Ten

Top Ten Most Important things to Remember

1. Why does the headrest protect you when you are in a car accident?

-  When the car is moving everything in the car is moving, when the car comes to an abrupt stop everything attached to the car will come to a stop, but everything not attached to the car will continue to move. We know this because of Newton’s first law → an object in motion will remain in motion until an outside force acts upon it. Since our heads continue to move the headrest will protect our head’s and necks from overextending.

2. When falling through the air a piece of paper crumpled up goes faster than an uncrumpled piece of paper why?
-the crumpled up piece of paper has less surface area and needs to go faster to reach fair. The larger surface area does not need to go faster to reach its fair.

3.How does a motor work?
-A motor consists of a magnet and a current carrying wire. the magnetic field exerts a force on the wire. this force will cause a torque. the torque will ultimately start the wire moving if the wire is perpendicular to the magnetic field. Once the wire is turning the blades will turn.

4. What happens as someone falls through the air?

-air resistance will grow as he gets faster and will eventually be equal and opposite (netforce=0). and there will be a constant velocity (equillibrium). Fweight is constant, fair is growing. It stops when fair becomies equal to it’s fweight. *Velocity increases until it reaches a constant speed. the Netforce is decreasing and will eventually reach 0, as will the acceleration.

5. How does a horse pull a buggy

-The reason the horse and teh buggy move forward is because the horse pushes the buggy harder than the buggy does. Both the horse and the buggy pull eachother with the same force. We know this because of Newtosn 3rd law which is every reaction has an equal and opposite reaction.

6. How does a computer read your credit card number
-there is a coil of wire (not current filled). On the credit card there are a series of magnet. when the magnets pass through the loop of wire, the magnetic field will change. this change will then induce a current. Finally the current will act as a signal to tell the computer what your credit card number is.

7. When you are riding in a car and it makes a Uturn you feel like you are forced to go sliding out of the car...why?

-Intertia-doing what you already want to be doing. centripital force-center seeking force, keeps you going into a curve. and the centrifigal force, which is a center fleeing force.

8. Why are train wheels shaped like they are?

-Because the wheels are self correcting and when the train shifts to the left the larger diameter of the wheels are on the left track and the smaller diameter of the wheels is on the right track. Therefore, the smaller diameter is slower tangentially and the larger ones are faster. Therefore, the train will curve to the left, keeping it on the track.

9. Why does the paperclip stick to the magnet?

-domains in a paper clip are random. (domains=cluster of electrons spinning in the same direction) the magnet has a magnetic field. when the magnet gets close to the paperclip the domains of the paperclip alighn to match the magnetic field of the magnet. The paperclip now has a north and south pole. The north pole of the paperclip is attracted to the south pole of the magnet thus the paper clip sticks to the magnet.

10. How does a generator work?

-Mechanical energy in → electrical energy out. move magnets over spinning wires which changes the magnetic field of the wires, which induces a voltage, causing a current and the current is used to run the lightbulb or blender.