如图所示:一正方体木块置于水平桌面上,若从高度的处将它沿水平截面切去一半,则余下部分对桌面的压力、压强与原来相比,是( )A.压力减半,压强减半 B.压力不变,压强减半C.压力减半,压强不变 D.压力不变,压强不变 答案:【答案】A【解析】试题分析:物体在水平桌面上,对桌面的压力F=G=mg,若将它沿水平方向截去一半,其重力减去一半,对地面的压力会减小一半;但是其受力面积不变,由压强公式p=即可知木块对桌面的压强变化.解:因为在水平桌面上,所以对桌面的压力等于其重力,F=G,水平切去一半后,G变小减半Six Chinese surveillance ships have entered waters
near islands claimed by both China and Japan.
China said the ships were carrying out "law
enforcement" to demonstrate its jurisdiction(管辖权) over the islands, known as Diaoyu in China and
Senkaku in Japan.
At least two of the vessels left after the Japanese
coast guard issued a warning, Japanese officials say.
The move came after Japan sealed a deal to buy three
of the islands from their private Japanese owner. Japan controls the
uninhabited but resource-rich East China Sea islands, which are also claimed by
Taiwan.
The Japanese Coast Guard said the first two Chinese
boats entered Japan's territorial waters at 06:18 local time (21:18 GMT
Thursday), followed by another fleet of four other ships just after 07:00. The
first two ships then left the area. A third ship left later on Friday morning,
one report said. No force was used, Japanese officials added. "Our patrol
vessels are currently telling them to leave our country's territorial
waters," the coastguard said in a statement.
The Chinese foreign ministry confirmed that its ships
were there. “These law enforcement and patrol activities are aimed to
demonstrate China's jurisdiction over the Diaoyu Islands and its affiliated(附属的) islets and ensure the country's maritime(海事的) interests,” a statement said.
The US has called for ''cooler heads to prevail'' as
tension intensifies between China and Japan over the islands, which lie south
of Okinawa and north of Taiwan. US Defense Secretary Leon Panetta is due to
visit both Japan and China from this weekend as part of a tour of the region
that also includes New Zealand.
The dispute has seriously marred diplomatic relations
between China and Japan and threatens to damage the strong trading
relationship, says the BBC's John Sudworth in Beijing. The row(争端) has also generated strong nationalist sentiment on
both sides that observers say now makes it very difficult to be seen to be
backing down, says our correspondent.
The Japanese government says it is buying the islands
to promote their stable and peaceful management. Its move followed a bid by
right-wing Tokyo Governor Shintaro Ishihara to buy the islands using public
donations - an action that would likely have further provoked(触怒) China.
China, on the other hand, says the islands have
historically been its territory and fishing grounds.
Meanwhile Japan's newly-appointed ambassador to China,
Shinichi Nishimiya, remains in hospital in Tokyo after he was found unconscious
near his home in Tokyo on Thursday. No details have been given on his
condition. He was appointed on Tuesday to replace Uichiro Niwa, who has been
criticised for his handling of one of the worse diplomatic rows between Japan
and China in recent years.
1.The Diaoyu Islands are actually inhabited by .
A.Japan B.China C.America D.Nobody
2.Which of the following is true?
A.Japan fired
at the 6 Chinese ships to warn them to leave the waters.
B.China
admitted that the 6 ships had been forced to leave the waters.
C.The US called
on both sides to calm down.
D.Shinichi
Nishimiya was unconscious in the hospital because somebody attacked him.
3.Why was Uichiro Niwa replaced?
A.He is not
iron enough in handling the diplomatic rows between Japan and China.
B.His health
condition is not good enough to work there.
C.He didn’t do a good job in dealing with the dispute about the
Diaoyu Islands.
D.He criticized
the Chinese government publicly in an improper way.
4.This news report is most likely to be selected from
the newspaper.
A.British B.Chinese C.Japanese D.American