最爱做这种题了
1.a=F/m=2s=1/2at^2=4mv0^2-0=2asv0=4W=Fs=24J2.恰能过定点C说明在C点，向心力等于重力即mg=mv^2/Rv^2=gR1/2mvo^2=2mgR+1/2mv^2R=8/25
