This creates a readily available ground or return throughout the car. It reduces the need to run a ground wire to every location that needs a return; dashboard, interior lights, tail lamps, ignition system, head lights, etc...
The negative lead of the battery charger can be connected to either the battery negative terminal/post, the alternator case, or a known good engine or chassis ground. Note, if the lead is placed on a painted surface, high resistance will occur and the system will not charge.
It depends on the case / chassis. Most computer cases use the 6-32 screw, which is the same screw used to attach hard disks to the chassis. However, I have seen some that use the other M3 style, which is used to attach CD-Roms and floppy drives to the chassis. http://en.wikipedia.org/wiki/Computer_case_screws
There is no way that the positive battery terminal was ever connected to the chassis. This would be a dead short and would fry the battery. Negative to chassis is correct, but positive to chassis, no way. That positive cable goes somewhere else.
Positive to positive and negative to negative. The negative will be connect to the engine or chassis. The positive will be connected to the starter.
Negative (-)
Look for holes in the vehicle chassis. Do not attach to the bumper or the axel.
A chassis (in French, "sha-SEE" & in English, "CHAss-ee") is a base for something to be built upon. In cars, the chassis is the framework that the rest of the car and engine attach to. In a big old TV set, the chassis was the bottom part that had all the tubes, wiring, and other electronics.
The entire metal chassis and body is grounded with the negative side of the battery.
Cars in which the positive terminal of the battery is connected to the chassis. They require specially designed components built for positive ground cars. The usual configuration is a negative ground (the negative battery terminal connected to the car's chassis).
They're usually sightly differently shaped to attach well to the strut and the chassis.
The term, 'negative ground' or 'negative earth' refers to the system of chassis-grounding, or chassis-earthing, used in vehicles. With this system, the negative terminal of the battery is directly connected to the metal parts of a vehicle, while the positive terminal is connected to the various electrical devices (lamps, etc.) using insulated conductors. The vehicle's metal parts ('chassis') then act as the return conductor to the battery.
There is a strap which you wrap around your wrist and a wire with a clip on the end. Attach the clip to the chassis of the computer to eliminate static electric discharge. Any difference in voltage between the chassis and you will flow through the wire and be neutralized.