物体以速度v匀速通过直线上的A、B两点，所用时间为t；现在物体从A点由静止出发，先匀加速直线运动（加速度为a₁）到某一最大速度v_m后立即做匀减速直线运动（加速度大小为a₂）至B点速度恰好减为0，所用时间仍为t．则物体的（　　）

    In northern Scotland there is a long deep lake called Loch Ness.  More than 200 meters deep, it is the largest lake in the UK.  People  say  a  big monster (怪兽)  lives in its dark, cold waters. It weighs more than 1,000 kilos and is at least ten meters long. Some people say it has a head like a horse. Others say it looks like a snake. Many people travel to Loch Ness to look for this strange monster, but only a few people have seen it. At least, they say they have seen it.

    The Loch Ness Monster is a famous legend (传说). The first story about a monster in Loch Ness was told over 500 years ago, but the legend of the monster spread widely only in the twentieth century. In 1933, a husband and wife reported that they saw a big monster in Loch Ness. Several people have taken photos, but at least one of them was a hoax (骗局). During the 1960s, a team was formed to look for the monster. They took many photos and made movies, but they were never able to find a monster.

    There is no real fact that a monster lives in Loch Ness, but there is also no fact that one doesn't live. One thing is true about Loch Ness: there are a lot of tourists there.

小楠想探究某电阻的阻值R，与温度t的关系，设计了如下图所示的电路，其中，定值电阻R₀＝20欧，电源电压U＝3伏。他把该电阻放在不同的温度下做实验，得到了不同温度下该电阻的阻值(如下表)。