# Automobile or Related Car Terms

#### (scientific terms about the use of vehicles including cars, trucks, or any automobiles including their technology as related to transportation)

horsepower
A measurement of the amount of power a car engine can produce.

In metric units, one horsepower = 746 watts or roughly the power produced by twelve 60-watt light bulbs.

hybrid car
Hybrid cars have two sources of power:
1. An ordinary gasoline engine, powered by a fuel tank.
2. An electric motor, powered by batteries.

The driver can switch between gasoline and electric power to suit different driving conditions.

hydraulics
A hydraulic system can transmit force between two places by pushing fluids through tubes of different sizes.

Hydraulic pipes power the brakes on most cars. They also power the lifting rams on bulldozers and cranes.

hydrogen
A light, invisible, and highly flammable gas that can be used to make power in a fuel cell.
inertia
The tendency of objects in motion to remain in motion, and objects at rest to remain at rest, unless acted upon by some outside force; such as, friction.

Moving objects usually grind to a halt because there is a force, or friction, trying to stop them, but if the force of friction is taken away as in space, then Newton's first law explains the function that keeps the stars, planets, and moons continually moving.

internal combustion engine
An engine that burns fuel inside closed metal cylinders.

External combustion engines; such as, steam engines, produce power less efficiently by burning fuel in an external chamber to heat a liquid or gas, which then moves a piston or a turbine.

### Each piston in an internal combustion engine makes four "strokes"

The four-stroke cycles include explosions inside the engine's cylinders, on top of the pistons, and the blast force pushes the pistons down; then, the crankshaft swings around and pushes the pistons back up for the next stage in the cycle. The cycles for one piston are described in the following sequences:

1. The piston moves down, sucking in air through the inlet valve while a tiny squirt of gasoline is injected into the air.
2. The inlet valve at the top closes, trapping everything inside and then the piston moves up, squeezing the air and gasoline tightly together.
3. When the piston reaches the top, a carefully timed spark sets fire to the gasoline; as the gas burns explosively, forcing the piston back down.
4. Finally, the piston moves back up and pushes the burned gases out of the outlet valve which leave the car through the exhaust.
jet engine
An engine that makes power by burning a continuous stream of fuel and air.

A jet engine moves a plane or car forward by firing a stream of hot gas backward; a scientific idea known as action and reaction or Newton's third law.

kinetic energy
1. When something moves, it is said to have kinetic energy.

To make a moving car stop, all its kinetic energy must be converted into other forms by heating up the brakes, for example.

2. The energy that a moving body possesses because of its motion, dependent on its mass and the rate at which it is moving; equal to 1/2 mv2, where m is mass and v is velocity.
kinetics
The branch of mechanics concerned with the relationship between motion, force, and mass.
machine
1. In science, any device that transmits or modifies power, forces, or motion to do work can be classified as a machine.

A wrench, a jack, and a crowbar, used for changing tires are all "simple machines".

2. Any device that transmits, modifies, or magnifies forces for a specific purpose.

Machines typically either alter the amount of force applied, or the direction along which it is applied. A simple machine is a machine with only one or two parts.

mass
The amount of matter contained in a body; measured in grams, kilograms, or tons.
mechanical
A description of any device that works using moving parts; unlike an electrical or electronic device, which may have no moving parts.
momentum
The tendency of a moving object to keep moving.

The momentum of an object is its mass times its velocity, so trucks generally have more momentum than cars, and fast-moving cars have more momentum than slower ones.

piston
A tight-fitting plunger that moves up and down inside an engine cylinder, pushed by the force of exploding fuel.

The pistons power the crankshaft and energy from the pistons drives the gearbox and ultimately the wheels. It is also used in shock absorbers to convert the energy of bouncing suspension springs into heat.

pollution
A harmful or otherwise unwanted chemical created when engines burn fuel.

Exhaust pollution is a mixture of gases; such as, carbon monoxide and solids including soot.

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