Automobiles


Automobiles (also called cars) are the main transportation in the word today after feet.
Today cars in North America are considered a necessity. When the first car was made (Model-T
Ford) it was only one color (black) with no radio, no heater, basically it was just a little motor on
four wheels. Today all cars in North America come with heaters, radios and options like
air-conditioning , cruise control, CD players, in some Mercedes you can get TVís in the back of
the front seats with Nintendos in them.
I say you expect these things in North America because Iíve been fortunate enough to see
what cars look like on the island of Barbados. They donít have heaters, but I guess you donít
need them. They donít even have radios unless youíre lucky.

How do cars move? Stop moving?

Cars move because they have a motor that provides them with a force that makes the
wheels turn around. If one thing in the entire engine breaks then the car will not move (or move
slowly). The tires donít provide enough friction to stop a car so the brakes are needed to apply a
force to stop it.
How a brake works is like so: It pushes down on the wheel with such a force that the
friction between the brake pad and the wheel will slow down to a stop.

Does anything help it to move?

The shape of the car is a great aid, just look at the difference between cars made in 1985
with the ďboxĒ look and the round cars made today. The cars made today allow the air to move
around it easier, so their drag is less.
Tires help cars to move, just think about driving in a snow storm with summer tires on.
Thats a big NO, NO! The friction is so little that the car just slides and you wonít be able to
control where you want the car to go. So in the winter we either get studded tires or tires with
bigger treads on them.

Does anything affect it to move?

Some of the shapes of cars today are tall and short in length. When this is the case the
car would not drive straight on windy days. One example is with Jeeps or the New Beatle.
Because of the shape of the New Beatles they need spoilers that keep them close to the ground
because the car would liftoff the ground from the air moving under it.

Car builders need to know physics because they need to know things like the
maximum velocity and acceleration so the car can handle properly to the drivers instructions.
Velocity is how fast the car goes. On cars this isnít in m/s but in km/h or miles/h.
Cruise control allows you to keep your velocity constant. This option is good for highway
driving but is not recommended for city use.
Acceleration and deceleration are used in a few different ways. To make the car do
either it must sift gears or the car while overheat. Acceleration is used when starting from a stop
but isnít used as much afterward because of speed limits. Depending on the POWER of the car
it could accelerate from 0-100 km/h in 5-15 seconds.
Forces are needed to make the wheels turn and not turn. The motor needs to push on the
wheels with a certain force or the car wonít move.