"I was just like you--I’ thought I was invincible," says Adam Blomberg, standing before 400 students in a darkened auditorium at Miami’s Coral Reef Senior High School. A photo of a bloodied and unconscious teenager, a breathing tube protruding from his mouth, flashes on the wall.
"That was me," he says. There’s a collective gasp before the room grows silent and Blomberg,31, an anesthesiologist who trained at Brigham and Women’s Hospital in Boston, begins the story of what happened one night in February 1995.
He created a presentation illustrating the dangers of behaving irresponsibly in a car, from not buckling up to speeding to driving under the influence of alcohol and drugs. He tracked down photos of teen crash victims from the center’s archives, then incorporated statistics and his own experience. He spoke the first time to a local Boy Scout troop and was soon giving his talk, "A Survivor’s Story," at high schools around the state.
The Blomberg family had reason to celebrate. Adam had fully recovered and was on his way to fulfilling his lifelong dream of becoming a doctor. But in January 2000, Blomberg’s 22-year-old step-brother, Michael, was killed in a crash while driving to his Atlanta home late one night. He wasn’t wearing a seat belt. After the accident, Blomberg stopped telling his story to crowds, racked with guilt over his inability to reach Michael. If Blomberg had failed his own brother, he reasoned, how could he possibly make a difference to a roomful of strangers Requests from schools continued to roll in, but he turned down every one.
Then Blomberg got a call from a high school counselor. As he started into his standard excuse-lack of time—he looked across the room at a stack of thank-you notes from students who had heard him speak. He realized that kids needed to hear what he had to say. He agreed to visit the school and began contacting others on the waiting list for his talks.
Blomberg leaves the school hoping he has changed someone’s behavior. He recalls a letter he received from a student who heard him speak and got into a crash later that same day but was unharmed. " She told me she was wearing her seat belt because of me."
Letters like this reinforce his belief that he survived the accident for a reason. "There are a lot of physicians in the world, and we all save lives," he says. "I have a special opportunity to save lives not just as a doctor but also as a human being.\
Which one of the following is NOT a part of the author’s presentation（）
A. Photos
B. Statistics
C. Videos
D. His own experience
，第5秒内加速度
，根据牛顿第二定律
可知合外力大小之比等于加速度之比，即在第1s内受合外力大小是第5s内受合外力大小的2倍答案C对。速度时间图像与时间轴围成的面积代表位移，时间轴以上部分表示位移为正方向，时间轴以下部分表示位移为负方向。据此前三秒位移为
后四秒位移
，前七秒内的总位移为
，平均速度
答案A错。.在1-3s的位移位移为正，3-5s的位移为负，方向不同答案B错。.在第3s末距离0时刻所在的位置即前三秒的位移为