如图所示，体积为500cm³的长方体木块浸没在装有水的柱形容器中，细线对木块的拉力为2N，此时水的深度为20cm。（取g=10N/kg），如图所示，求：

（1）水对容器底的压强。；

（2）木块受到水的浮力。

（3）木块的密度。

（4）若剪断细线待木块静止后，将木块露出水面的部分切去，要使剩余木块刚好浸没在水中，在木块上应加多大的力？

A

Music

Opera at Music Hall: 1243 Elm Street. The season runs June through August, with additional performances in March and September. The Opera honors Enjoy the Arts membership discounts. Phone: 241-2742. http://www.cityopera.com.

Chamber Orchestra: The Orchestra plays at Memorial Hall at 1406 Elm Street, which offers several concerts from March through June. Call 723-1182 for more information. http: //www.chamberorch.com.

Symphony Orchestra: At Music Hall and Riverbend. For ticket sales, call 381-3300. Regular season runs September through May at Music Hall in summer at Riverbend. http://www.symphony.org/home.asp.

College Conservatory of Music (CCM): Performances are on the main campus(校园) of the university, usually at Patricia Cobbett Theater. CCM organizes a variety of events, including performances by the well-known LaSalle Quartet, CCM’s Philharmonic Orchestra, and various groups of musicians presenting Baroque through modern music. Students with I.D. cards can attend the events for free. A free schedule of events for each term is available by calling the box office at 556-4183. http://www.ccm.uc.edu/events/calendar.

Riverbend Music Theater: 6295 Kellogg Ave. Large outdoor theater with the closest seats under cover (price difference).Big name shows all summer long! Phone:232-6220. http://www.riverbendmusic.com.

Which number should you call if you want to see an opera?（）

A.241-2742.

B.723-1182.

C.381-3300.

D.232-6220.