体积相同的实心铜块和铁块浸没在水中,铜块所受的浮力 ____ 铁块所受的浮力,铜块的质量 ____ 铁块的质量(ρ铜>ρ铁),铜块的重力与浮力的合力 ____ 铁块的重力与浮力的合力。(均选填“大于”、“等于”或“小于”)
He is a successful businessman. But he is so cruel that he has made a lot of ____ (敌人).