主页
学科
搜索
账户
常见问题
当前学科:第二章物理学
题目:
单选
一声波波源相对媒质不动,发出的声波频率是ν0。设以观察者的运动速度为波速的1/2,当观察着迎着波源运动时,他接收到的声波频率是()。
A . 2ν0',false,'ν0
B .
答案:
<查看本题扣1积分>
查看答案
答案不对?请尝试站内搜索
推荐知识点:
成班纵队(二路纵队)集合时,基准兵迅速到(),自行对正。
We"had a good many anxious moments,but everything__________ all right in the end.
哮喘与肺炎喘嗽的主要区别是()
当某一种期刊本馆没有收藏时,确定其他收藏馆的方法是()。
患者男性,25岁,在京务工,主因"发热、咳嗽、咳痰4天"到门诊就诊,在家未用任何药物,查体:右下肺实变体征,胸部X线示右肺大片浸润影,血气分析示pH7.36,PaO63mmHg,PaCO32mmHg。该患者入院后应首选哪种抗生素治疗()
关于离心式压缩机在稳定区内的工作情况描述不正确的是()。
内分泌性突眼见于()
母猪,3.5岁,体格偏瘦,怀孕114天时分娩,产出8个胎儿后努责微弱,40分钟后仍不见胎儿产出。B超检查可见子宫后部有多头活胎首选的助产药是()
胃大部切除术后数月或数年多发生的合并症为()
Im a 43-year-old mother of three young kids with a Master of Science degree. I also【C1】______pizzas for a living. I started doing it after【C2】______home with my children for four years. Caring for your kids all day is a【C3】______opportunity for many women, but it wasnt right for me. I began suffering from【C4】______and decided to get a job so Id have more of my own identity. Now I work nights when my husband is home so we dont have to【C5】______child care. After I learned the basics of pizza delivery—like getting the【C6】______together and not getting lost—I began my new "career" . Being【C7】______and organized by nature, 1 studied the tipping patterns of the town. Our community had a small, expensive liberal-arts【C8】______full of students who ordered lots of pizzas. Most of the kids were friendly and polite.【C9】______Friday and Saturday nights, some of the dorms had huge parties.【C10】______the stairs were sticky from beer and the music was so loud they couldnt【C11】______me knock on the door, the crowds of happy students shouting, "Pizza! Pizza!" always let me through. The first few days of each month, one of us drivers would take【C12】______turn covering the public-housing developments. These customers did not always tip well,【C13】______I always liked seeing the children and adults sitting outside and【C14】______the evenings when the weather was nice. I also deliver to multimillion dollar homes now, but the【C15】______I make in tips has stayed the same. As I【C16】______to these beautiful houses, its easy to fantasize about a【C17】______tip. The person who answers the door always【C18】______young and, like the members of my own family,【C19】______educated. All I usually get is a brief "Thank you" and a dollar or two. People might say Im crazy to waste my education, but I have【C20】______most of them dont: a job I love.【C1】A.buyB.waitC.turnD.deliver