[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$ftB85t8im-bXgy_MYe0-0peFxok3uDhzT8KF0iOru2_s":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":16,"related":17,"source":27,"type":28},[],"2026-05-08 01:21:23",361487755,[8,9,10,11],"847Hz","680Hz","720Hz","640Hz",{"courseId":13,"courseImg":14,"courseName":15},"53e1d2ef4961cca8eea3e23969ad2cb9","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F03a579384a6dc297c89809b582fcc767.png","默认课程","火车以60m\u002Fs的速度行驶时,在铁路旁与铁路平行的公路上有一汽车在火车后方以20m\u002Fs的速度与火车同向行驶,火车汽笛的频率为800Hz,坐在汽车中的人听到火车鸣笛声的频率为(已知空气中声速为340 m\u002Fs)",[18,29,38],{"answer":19,"createTime":5,"id":20,"options":21,"question":26,"source":27,"type":28},[],361487753,[22,23,24,25],"1059Hz","1000Hz","941Hz","889Hz","声源S和接收器R在一条直线上以20m\u002Fs相同的速度沿同一方向运动,设声波的传播速度为340m\u002Fs,声源振动频率为1000Hz,则接收器测得的频率为","v1",0,{"answer":30,"createTime":5,"id":31,"options":32,"question":37,"source":27,"type":28},[],361487754,[33,34,35,36],"νS","νS(u+vS)\u002Fu","νS(u-vS)\u002Fu","νSu\u002F(u-vS)","声源的频率为νS,声波在媒质中的传播速度为u.接收器R相对媒质静止,声源S相对于媒质以速度vS向接收器R运动,则接收器R接收到的声波频率为",{"answer":39,"createTime":5,"id":6,"options":40,"question":16,"source":27,"type":28},[],[8,9,10,11]]