RPM stands for "revolutions per minute", and are the amount of complete revolutions (360 degrees) a crankshaft spins in one minute. Also, it gives you an idea of how much work your engine is doing. The red line indicator on your tachometer, is an indication of very high RPM's, and should be avoided if possible. Generally your car cruises along the lines of 3,000 rpm. More than that, and you should probably go to a higher gear.
because the engine needs to have a 20 seconds RPMs
check engine mounts
The rpms need to be high enough to keep the engine running. Most engines need at least 850 rpms to keep from stalling.
If you mean why the difference in RPMs between idling and driving, the difference is due to the engine load; At idle, the engine isn't really doing much other than staying running, but under load (driving) the engine has to put its power out to the drivetrain, hence the symptomatic loss of engine speed (RPMs).
A Formula One engine reaches 18,000 RPMs.
If you have an engine that idles at 6000 rpms, you need to have it checked - immediately. Around 750 rpms would be normal.
The 60-horsepower VW engine has a torque specification of 115 pounds at 2000 RPMs. The engine will have 130 pounds of torque at 2500 RPMs.
The RPMs and the engine of the 2001 Oldsmobile Alero might surge if there is a problem with the oxygen or fuel sensor. It may also surge if there is a problem with the fuel injectors or the fuel filter.
horsepower isn't solely based on the engine liters. a car could have a 3.0 liter engine and be 5 years old and have lost 1-30 or more horsepower. age effects an engine a lot depending on care. max RPMs also effect horsepower. a car that somehow gained 200lbs+ in dead weight will effect its max RPMs. a ford torus isn't a sporty car so horsepower is generally low-mid range. generally 155 - 220hp 3.0 liter engine.
maybe your rpms gauge is broken.get it looked at by a professional
It depends on what type of car and what gear you are in
The more you push on the accelerator the more you increase the fuel/air mixture to the engine which will cause the engine to turn more RPMs, thus propelling the vehicle at a faster speed.