[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$f-gF7vBeYTyv9GoVVulVNTxRl-g0lyqUVudB1esjFT1k":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":19,"related":20,"source":24,"type":25},[],"2025-06-12 21:04:34",199443232,[8,9,10,11],"847Hz","680Hz","720Hz","640Hz",{"count":13,"courseId":14,"courseImg":15,"courseName":16,"workId":17,"workName":18},3,"05cc272230f763aa814d04fc4b242c05","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002Fb71f5ef0bc91dad807788d7bf753eb02.png","大学物理","work_42501827","作业11.9","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)",[21,26,36],{"answer":22,"createTime":5,"id":6,"options":23,"question":19,"source":24,"type":25},[],[8,9,10,11],"v1",0,{"answer":27,"createTime":28,"id":29,"options":30,"question":35,"source":24,"type":25},[],"2025-06-12 21:04:35",199443244,[31,32,33,34],"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":37,"createTime":28,"id":38,"options":39,"question":44,"source":24,"type":25},[],199443247,[40,41,42,43],"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"]