9、直角刚杆OAB在图示瞬时有<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/836ef9dab2c5422380bb37f4f480a932.png?x-oss-process=image/sharpen,200"/>=2rad/s，<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/2b571974913e4b8e912b2ff9bfc5747e.png?x-oss-process=image/sharpen,200"/>=5rad/s2，若OA=40cm，AB=30cm，则B点的速度的大小为___cm/s，法向加速度的大小为__cm/s2，切向加速度的大小为____ cm/s2。（6分）<br/> <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/944bc574430f4e84b00fda6c078dbb85.png?x-oss-process=image/sharpen,200"/>