如图所示，一根重8N的均匀直棒AB，A端用绳吊在固定点0，用一沿水平方向的力F=6N作用于B端，使棒处于平衡状态，则绳与竖直方向的夹角为（ sin37°=0.6 cos37°=0.8 ）（ ）
A．30°
B．37°
C．45°
D．60°
对直棒AB受力分析，受到重力mg、向右的已知力F、绳子的拉力T，如图
根据平衡条件，结合几何关系，有
tanθ=
=F mg
=0.756 8
故θ=37°
由于绳子的弹力沿着绳并指向绳子的收缩方向，故绳子与竖直方向的夹角为37°
故选：B．
| 在B栏中找出A栏英语句子的正确答语。 |
| (A) ( )1. Do you walk to school? ( )2. How do you go to school? ( )3. Does your father drives to work? ( )4. Where does your uncle work? ( )5. Do you go to school by car? | (B) A. Yes. He has a car. B. He works in a store. C. No. I ride my bicycle. D. Yes. I live near school. E. By bus. |