问题 单项选择题

半径为R的圆盘以匀角速度w沿水平滚动而无滑动,AB杆的A端与圆盘边缘铰接,其月端在水平面上滑动。在图示位置时,AB杆B端的加速度aB大小为()。

A.A

B.B

C.C

D.D

答案

参考答案:C

解析:

此刻AB杆瞬时平动,vA=vB,[aA]AB=[aB]AB,而轮平面运动与地面接触点为速度瞬心,O点为加速度瞬心,aA=rw2,指向O。

单项选择题

B

Rae Armantrout, who has been a poetry professor at the University of California San Diego (UCSD) for two decades, has won the 2010 Pulitzer Prize in the poetry category for her most recent book, "Versed".

"I’m delighted and amazed at how much media recognition that the Pulitzer brings, as com-pared to even the National Book Critics Award, which I was also surprised and delighted to win," said Armantrout.

"For a long time, my writing has been just below the media radar, and to have this kind of at-tention, suddenly, with my 10th book, is really surprising. "

Armantrout, a native Californian, received her bachelor’s degree at UC Berkeley, where she studied with noted poet Denise Levertov, and her master’s in creative writing from San Francisco State University. She is a founding member of Language Poets, a group in American poetry that analyzes the way language is used and raises questions to make the reader think.

In March, she won the National Book Critics Circle Award for "Versed".

"This book has gotten more attention," Armantrout said, "but I don’t feel as if it’s better. "

The first half of "Versed" focuses on the dark forces taking hold of the United States as it fought the war against Iraq. The second half looks at the dark forces casting a shadow over her own life after Armantrout was diagnosed with cancer in 2006.Armantrout was shocked to learn she had won the Pulitzer but many of her colleagues were not. "Rae Armantrout is a unique voice in American poetry," said Seth Lerer, head of Arts and Humanities at UCSD.

"Versed", published by the Wesleyan University Press, did appear in a larger printing than her earlier works, which is about 2,700 copies. The new edition is scheduled to appear in May.

 

What can be learned about "Versed"()

A.It consists of three parts.

B.It is mainly about the American army.

C.It is a book published two decades ago.

D.It partly concerns the poet’s own life.

单项选择题