landing
It can be anywhere between 80 and 140 knots depending on aircraft
VSTOL = Vertical or Short Take Off and Landing aircraft. Whereas a STOL aircraft is a Short Take Off and Landing Aircraft. Maybe there is a term VTOL just for Vertical Take Off and Landing.
VSTOL: verticle or short take of and landing
The wheels along with the system is called Landing Gear. The Landing Gear can be retracted soon after take-off. Stationary landing gears slow the aircraft down.
The lift off speed is dependant upon the weight of the aircraft. The heavier the aircraft the higher the speed. At maximum take off weight of 875,000 lbs (396,890 kgs) Vr (rotation speed) will be about 175 knots and V2 about 185 knots.
It is the system of wheels that opens before an airplane lands and closes after take off. The system also supports the aircraft while on the ground, taxiing or landing.
Probably any helicopter or VTOL (Vertical Take-Off and Landing) aircraft. http://en.wikipedia.org/wiki/VTOL
There is no term as a roller landing, however there is a term "roller" being replaced by "touch and go". This is where an aircraft comes into land but instead of stopping on the runway, it takes off again. This simulates a landing and a take off all in one maneuver.
You apply take-off power by pushing the TOGA switch on the front of the thrust levers, when the aircraft speed reaches the letters Vr on the speed display you pull back on the control column until the aircraft is climbing away from the runway. You then raise the landing gear. I strongly suggest you then push the AP (Auto pilot) button in front of you.
to take off the the aircraft which is operated at a specific speed on the runway
Light propeller driven aircraft can take off as low as 50 mph. Basically the heavier an aircraft is, the higher speed it takes off. - A fully laden 747 will take off at approximately 170 mph.
The flaps on an aircraft are on the trailing edge of the wing and vertical stabiliser on the tail and are hinged to wing downwards. By bringing these down the stall speed of an air craft may be reduced allowing it to slow down more upon landing and to be able to reach air speed more quickly upon take off.