A:with; with
B:with; of which
C:of; which
D:of; from which
如图所示,光滑水平面上,小球m在拉力F作用下做匀速圆周运动.若小球运动到P点时,拉力F发生变化,关于小球运动情况的说法正确的是( )
45−34 =____
56+23 =____