What do the different gears do?

I'm 17-year old girl and I drive a 1999 Mercury Sable. It's an automatic obviously, and it has a V6 engine. What do the different gears do and how can I get more speed when I first accelerate? (Layman's terms please, I know absolutely nothing about cars but I'm trying to learn)

The lower gears provide more torque to the driving wheels. Sorry if this isn't enough, some guru will come in and add some math to this. :)

Well having an automatic you have what we call taller gearing since I am guessing it is a three speed. This means that the gears in your transmission are bigger. You can put a manual transmission in and get shorter gearing, or smaller gears. Larger gears allow for more speed in a gear while smaller gears allow for faster acceleration. Since there are more gears in the manual, a five or possibly six speed, the car can still go as fast it just has to have more gears. You can always get closer geared automatics, but in a three speed you will expect a serious decrease in cruising speed.

Since your car is a FWD you may just want to look into selling your car if you wanted to switch to a manual.

all cars have a power band, which is a range of rpm say 3500-5000 this is where you acheice max torque/horsepower, gears are used in cars to accomidate this power band at all speeds of the car, for example doing 15 in 5th gear wouldnt work because you would need to being doing very low rpm, and alternatively 60 in 1st you would need high rpm...

a way to get of the mine quickly would be to put your auto in first then gun it... DONT FORGET TO PUT IT BACK INTO DRIVE, this method is fairly bad pratice for non-performance gearboxes but it will get you going pretty quick... so to speak:D

As a general rule of thumb, the lower your gear ratio is, the slower your car will be off the line but you will have a higher top end speed. For example, if your car has 2.73:1 gear ratio chances are it will be slow off the line but will be able to attain a higher top end speed. If your vehicle has 3.73:1 gears it will be much quicker off the line but will also have a lower top end speed. Horsepower and torque ratings do play a part in making a car faster as the engine drives the transmission and the tranny drives the differential. Also 2.73:1 gears means that for every 1 turn of the driveshaft, the drive wheels will turn 2.73 times. So if you increase the gear ratio, you will increase the amount of revolutions the drive wheels make and this will produce quicker launches. Changing gears is probably the easiest way to lower your 1/4 mile E.T.'s, but on front wheel drive cars it usually means getting the tranny rebuilt with different gears or buying another tranny that has different ratios to begin with. Hope this info helps you.

have you ever ridden on a bike with diff speeds on it? like where you can shift gears? well thats kinda how it works, but bikes usually have more gears, like 18 gears or something like that, and two seperate areas to hold gears, which is the one on your pedals, and the other on the rear wheels. gears in cars are like the gears in bikes, the bigger gears help you take off easier, and as you go faster you can switch to smaller gears so you dont have to pedal so fast. basically, bigger gears in the begginning, and smaller gears at the end.

have you ever ridden on a bike with diff speeds on it? like where you can shift gears? well thats kinda how it works, but bikes usually have more gears, like 18 gears or something like that, and two seperate areas to hold gears, which is the one on your pedals, and the other on the rear wheels. gears in cars are like the gears in bikes, the bigger gears help you take off easier, and as you go faster you can switch to smaller gears so you dont have to pedal so fast. basically, bigger gears in the begginning, and smaller gears at the end.

I wonder what the torque range of a human is? pedal wise... hook it up to a dyno :P but hey you can still call it HP uhh Human power :)

the human rpm on a cycle is somewhere between 150-`200 rpm makeing between .75 and1.5hp