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)

The force of air resistance that slows a car as it moves faster.

At high speeds, virtually all a car's energy is used to overcome drag.

Any of various devices used in testing a motor or engine for such characteristics as efficiency and torque; especially, a device used to simulate road conditions and loads in stationary settings and to gather data about vehicle performance under those conditions.
The fraction of the energy that a machine uses effectively compared with how much is put in.

A typical gasoline engine is 30 percent efficient, so it uses 30 percent of the energy in the gasoline to move the car forward and wastes the other 70 percent, mostly as heat.

The tendency of a material to return to its original shape if a force is applied and then removed.

A car's rubber tires are elastic, so they spring back to shape after running over bumps in the road.

electric motor
A machine that uses electricity and magnetism to power an axle.

An electric motor converts electrical energy into mechanical energy.

electric motor vehicle
A motor vehicle powered by an electric motor that draws current from rechargeable storage batteries, fuel cells, photovoltaic arrays, or other sources of electric current.
A property of matter that has the ability to make something happen through movement or a change in condition.

These changes can be physical or chemical, and allow energy to be converted to another form; for example, the chemical energy of fuel is converted into heat and then into mechanical energy in an engine.

A pushing or pulling action that can make objects speed up or slow down, change direction, or change shape.
The rubbing force between two surfaces that come into contact.

Friction between the tires of a car and the road beneath tends to slow it down, as does the friction between air moving around a car and the metal bodywork.

A substance or any material that can be used to provide power for an engine or which can be burned in air to release energy.

Fuels; such as, gasoline are made mostly of hydrocarbons (carbon and hydogen molecules).

fuel cell
An electrical device powered by fuel from a tank that makes energy through a chemical reaction.

A fuel cell is similar to a large battery, but where a battery gradually runs down, a fuel cell runs continuously for as long as there is fuel in the tank.

fuel-cell cars
A fuel cell is a type of battery which converts the chemicals hydrogen and oxygen into water, and in the process produces electricity.

Hydrogen is pumped into the cell from an on board tank, while the oxygen is taken from the air outside. Together they form steam, which is emitted through the car's exhaust.

Some car makers are putting a lot of time and effort into developing hybrid cars where the electric motors are powered by fuel cells.

Hydrogen is the most abundant element in the universe, but it is highly flammable; that is, it bursts into flames easily and as the lightest gas, it just floats away. Even so, it can be extracted from water, fossil fuels, and other substances.

The problem is to compress, or squeeze, hydrogen into a tank small enough to fit in a car. The tank can be topped off with hydrogen at refueling stations, but there are very few of such places available at this time.

The advantages and disadvantages of fuel-cell cars

    In theory, electric-fuel-cell cars could be the answer for clean cars of the future:

  • Fuel cells are reliable and make little noise since they have no moving parts.
  • Water is the only thing emitted through the exhaust.
  • There are a number of challenges still to be overcome:

  • Increasing the amount of electricity produced so the car has more power.
  • Compressing and safely storing enough hydrogen into a small tank for hundreds of miles of driving.
  • Making affordable cars which are now very expensive in that a fuel-cell system costs ten times more to make than a conventional engine.
—Compiled from excerpts found at
Car Science, An Under-the-Hood, Behind-the-Dash Look at How Cars Work
by Richard Hammond; DK Publishing; New York; 2008; pages 84-85.
A wheel with teeth cut into its edge that meshes with one or more similar wheels to increase the speed or torque of an engine.

The gearbox in a car contains gear wheels of different sizes that mesh together to make the car go faster, increase its climbing power up hills, or drive in reverse.

1. Gravitational force at the surface of a planet or other body that pulls mass toward its center.
2. The pulling force (force of attraction) between any two masses in the universe.

On earth, gravity is experienced as a downward force that makes things fall toward the ground.

1. A form of energy released by atoms and molecules moving around randomly.
2. The transfer of energy from one substance to another one.

The energy flow will always be from the warmer substance (with a higher temperature) to the cooler substance (at lower temperature).

Amounts of heat are expressed in energy units; such as, the calorie, the joule, and the BTU or British Thermal Unit which is about 252 calories and about 4.2 calories is a joule (the basic unit of energy in the meter-kilogram-second system).

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