tan37=v0/gt 10.5gt^2=h 21.2解的v0=3m/s物体以初速度v0做圆周远动 该过程动能守恒0.5mv^2+mg(R-h)=0.5mV^2 3F向心=mV^2/R 4解的F向心=36nF向心=FN-MGFn=46n
