The inside story-Automobile.
For a car to move on the road,the rear or front wheels should be rotated.For this to happen the power from the engine should reach the wheels.
The engine produces power in the form of turning effort(Torque) and angular speed(RPM). To start with, the driver presses the accelerator pedal lightly and therefore, only small amount of diesel is injected into the engine and burnt. The resulting power in it's present form is insufficient to move the car from rest. The Transmission system in the car provides a means to increase the torque and decrease the speed input to the wheels to enable the car to move on.The transmission system also varies the torque and speed input to the wheels to suit different driving conditions such as city drive, cruising on a highway and going over a gradient(bridge,uphill) depending on gear selection and accelerator pedal position.