题目

The first Starbucks coffee shop opened in 1971 in downtown Seattle, Washington, in the United States. It was a small coffee shop that roasted its own coffee beans. The coffee shop’s business did well, and by 1981 there were three more Starbucks stores in Seattle. Things really began to change for the company in 1981. That year, Howard Schultz met the three men who ran(经营) Starbucks. Schultz worked in New York for a company that made kitchen equipment. He noticed that Starbucks ordered a large number of special coffee makers, and he was curious about the company. Schultz went to Seattle t在做“研究匀变速直线运动”的实验时，某同学得到一条用打点计时器打下的纸带如图所示，并在其上取了A、B、C、D、E、F等6个计数点（每相邻两个计数点间还有4个打点计时器打下的点，本图中没有画出）打点计时器接的是220V、50Hz的交变电流．他把一把毫米刻度尺放在纸带上，其零刻度和计数点A对齐．（下述结果均保留两位有效数字）（1）由以上数据计算打点计时器在打C点时，物体的瞬时速度vC是0.160.16m/s；（2）计算该物体的加速度a为0.420.42m/s2；（3）如果当时电网中交流电的频率是f=49Hz，而做实验的同学并不知道，那么由此引起的加速度的测量值比实际值偏大大（填“大”或“小”）．