题干

一台天平由于使用时间较长,砝码磨损后,砝码的质量变小,当将天平调整平衡后,再用它来测量物体的质量,则其读数()

A.比标准值小
B.比标准值大
C.与标准值一样
D.无法判断

A:比标准值小

B:比标准值大

C:与标准值一样

D:无法判断

上一题 下一题 0.0难度 选择题 更新时间:2017-03-03 11:17:07

答案(点此获取答案解析)

B

同类题2

阅读理解

    Ben Lecomte, a French long-distance swimmer, dropped into the water Tuesday at Choshi, Japan, and embarked on his attempt to become the first person to swim across the Pacific Ocean, BBC News reports.

    Six years in the planning, the 5,500-mile effort is expected to take five to six months, with Lecomte swimming eight hours a day and covering an average of 30 miles daily, according to his website.

    His route to San Francisco will take him through the Great Pacific Garbage Patch, an area three times the size of France where large amounts of garbage and plastic waste have collected, CNN reports.

    Lecomte will be accompanied by a specially outfitted support boat named Discoverer. He will take rest periods on the boat, but it will return him to his stopping point each day to make sure he swims the entire distance.

    In addition to accomplishing a first, Lecomte said, he wants to draw attention to the problems of ocean pollution and climate change. A team of scientists plan to conduct research for 12 scientific institutions, including NASA and the Woods Hole Oceanographic Institution, while he is making his swim.

    Lecomte is no stranger to feats of long-distance open-water swimming. In 1998, he swam 4,000 miles across the Atlantic Ocean. On that swim he encountered sharks and stingrays. This time, he said, he will be wearing a shark-repellent bracelet.

    One of the challenges will be making sure he has enough energy each day, and Lecomte said he intends to consume 8,000 calories daily.