A:I went to Shanghai.
B:I'm going to Shanghai.
C:I go to Shanghai.
若直线经过A(0,1),B(3,4)两点,则直线AB的倾斜角为( )
人用绳子通过动滑轮拉物体A,A穿在光滑的竖直杆上,当以速度v0匀速地拉绳,使物体 A到达如图所示位置时,绳与竖直杆的夹角为θ,以下说法正确的是( )