![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
已知r为半径,则弧长为2πr/3的圆弧所对的圆心角为()
A.120°
B.120°/π
C.150°
D.150°/π
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
D、150°/π
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.120°
B.120°/π
C.150°
D.150°/π
D、150°/π
质点沿半径为R的圆周按的规律运动,式中s为
质点离圆周上某点的弧长,v0,b都是常量.求:(1)t时刻质点的加速度;
(2) t为何值时,加速度在数值上等于b。
A.3
B.q \f(3\r(3)+1,2)
C.4
D.2(eq \r(2)+1)