―I don’t have any change with me . Will you pay the fare for me?― A.Why don’t you bring any change with you? B.Nothing serious. C.Never mind. D.No problem. 答案:D如图所示,固定在小车上的支架的斜杆与竖直杆的夹角为θ,在斜杆下端固定有质量为m的小球,下列关于杆对球的作用力F的判断中,正确的是( )A、小车静止时,F=mg,方向竖直向上B、小车静止时,F=mgcosθ,方向垂直杆向上C、小车向右以加速度a运动时,一定有F=ma/sinθ.D、小车向左以加速度a运动时,F=(ma)2+(mg)2,方向斜向左上方