A:p是假命题,¬p::∀x∈(0, π2 ),f(x)≥0
B:p是假命题,¬p::∃x∈(0, π2 ),f(x)≥0
C:P是真命题,¬p::∀x∈(0, π2 ),f(x)≥0
D:p是真命题,¬p::∃x∈(0, π2 ),f(x)≥0
由万有引力定律F=G m1m2r2 可知,万有引力常量G的单位是( )