问题 选择题

关于功率的说法,正确的是(  )

A.速度大功率越大

B.作用力越大,功率越大

C.功率大的机器做功多

D.单位时间内做的功越多,其功率越大

答案

A、B、由公式P=

W
t
=
FS
t
=Fv知:物体功率的大小与作用力和速度都有关系,一个物理量不确定,功率大小就不能确定.此两选项都错误;

C、由公式W=Pt知,物体做功多少与功率和做功时间成正比,时间不确定,做功多少不能确定.此选项错误;

D、功率是单位时间完成的功,单位时间做功越多,所以功率越大.此选项正确.

故选D.

阅读理解

when Frida Kahlo's painting were on show in London, a poet described her paintings as " a ribbon(丝带) around a bomb". Such comments seem to suggest Kahlo had a big influence on the art world of her time. Sadly, she is actually a much bigger name today than she was during her time.

Born in 1907 in a village near Mexico City, Kahlo suffered from polio(小儿麻癖) at the age of seven. Her spine(脊柱) became bent as she grew older . Then, in 1925, her back was broken in several places in a school-bus accident. Throughout the rest of her life, the artist had many operations, but nothing was able to cure the terrible pain in her back. However, the accident had an unexpected side effect. While lying in her bed recovering, Kahlo taught herself to paint.

In 1929, she got married to Diego Rivera, another famous Mexico artist. Rivera's strong influence on Kahlo's style can be seen in her early works, but her later works from the 1940s, known today as her best works, show less influence from her husband.

Unfortunately, her works did not attract much attention in the 1930s and 1940s, even in her home country. Her first one-woman show in Mexico was not held until 1953. For more than a decade after her death in 1954, Kahlo's works remained largely unnoticed by the world, but in the 1970s her works began to gain international fame at last.

小题1:What does the phrase “ a much bigger name” in Paragraph 1 most nearly mean?

A.a far better artist

B.a far more gifted artist

C.a much stronger person

D.a much more famous person小题2:The terrible pain Kahlo suffered was caused by        .

A.polio

B.her bent spine

C.back injuries

D.the operations she had小题3:Kahlo’s style had become increasingly independent since the          .

A.1930s

B.1940s

C.1950s

D.1970s小题4:What is the author’s attitude toward Kahlo?

A.devotion.

B.sympathy

C.worry.

D.encouragement.

单项选择题