Vmcg & Vmca: increased air density ==> increased thrust from the engines. If one fails then you will need to be travelling faster to have enough tyre &/or aerodynamic authority to counter the now increased yaw.
V2: Can't remember.
V1: deleted because I was even more of a blithering idiot than usual
VR: Can't remember.
All from memory so I can't guarantee the accuracy!!!!
[ 12 July 2001: Message edited by: Tinstaafl ]