Okay let's see:
V1: The decision speed in the event of an engine failure during the takeoff roll at which it is possible to continue the takeoff and achieve the screen height within the normal takeoff distance available or to bring the aircraft to a full stop within the emergency distance available.
Thus, the takeoff must be abadoned with an engine failure below V1 and the takeoff must be continued with an engine failure above V1.
If the Takeoff Weight is limited by the Takeoff Distance Available (TODA), Takeoff Run Available (TORA), or Emergency Distance Available (EMDA), the V1 speed relates to a single point along the runway where the pilot will have the decision to continue or abort the takeoff in the event of an engine failure. V1 Cannot be less than VMCG; V1 cannot be greater than Vr or VMBE.
Vr: rotation speed where the speed at which the pilot initiates rotation during the takeoff to acheive V2 at the screen height even with an engine failuare. Vr cannot be less than 1.05 VMCA divide by 1.1 or 1.05 VMU.
V2: takeoff safety speed achieved by the screen height in the event of an engine failure that maintains adequate directional control and climb performance properties of the aircraft. To be more specific, V2 cannot be less than Vs x 1.20 and VMCA x 1.10.
V3: where the all-engine-operating takeoff climb speed the aircraft will achieve at the screen height.
V4: speed is the all-engine-operating takeoff climb speed the aircraft will achieve by 400' and is used as the lowest height where accleration to flap retraction speed is initiated.
VMU: minimum demonstrated unstick speed at which it is possible to get airborne on all engines and to climb out without hazard.
VMBE: maximum brake energy speed on the ground which a stop can be accomplished within the energy capabalities of the brakes.
I hope this will help!