高一物理问题,急于求解!!!!!!!!!!!!!!!!
推荐回答(3个)
1,题干有问题,因为肯定不是匀速滑下。既然AB=6m,BC=10m,小球经过AB、BC两段所用的时间均为2s,那么在AB和BC两段的平均速度之比肯定是6:10,看选项知道B合适
2.s=1/2*at^2
所以4s时的t为s时的两倍,而v=a*t,a是不变的,所以速度是2v,A
3.对匀加速运动的物体,他通过s的时间依次为1:(根号2-1):(根号3-根号2):(根号4-根号3):.....
所以呢1:(根号4-根号3)=t:2,选D
4.v=a*t;s=1/2a*t^2
v相等,所以s之比为t之比,选B
5.把它看做从0开始的匀加速运动,根据s=1/2a*t^2,可知是1:(4-1):(9-4)也就是1:3:5
6.S1=1/2a2*2;S=1/2a6*6=9S1,也就是有9节车厢;
前4秒经过s=1/2a*16=4S1,所以最后2s经过了5节车厢
前8节车厢经过要时间t 1/2at^2=8S1,得到t=根号32,所以最后一节时间是6-根号32=6-4根号2
答题很辛苦,满意就给分吧
我手机打字很吃力的,只告诉你第一个…
a=x/T2=4/4=1m/s2 则
1、一小球沿斜面匀速滑下,依次经过A、B、C三个点。已知AB=6m,BC=10m,小球经过AB、BC两段所用的时间均为2s,则小球经过A、B、C三点时的速度大小分别为(B)
A、2m/s ,3m/s ,4m/s B、2m/s ,4m/s ,6m/s
C、3m/s ,4m/s ,5m/s D、3m/s ,5m/s ,7m/s
2、由静止开始做匀加 速直线运动的物体,当经过s位的速度是v时,那么位移为4s时的速度是(A)
A、2v B、4V C、3V D、1.5V
3、将自由落体运动分成位移相等的4段,最后一段位移所用时间是2s,那么下落的第1段位移所用时间约是下面的哪个值(A)
A、0.5S B、1.7S C、8S D、7.5S
4、甲、乙两辆汽车速度相等,在同时制动后,均做匀减速运动,甲经3s停止,共前进了36m,乙经1.5s停止,乙车前进 的距离为(B)
A9m B、18m c、36m D、27m
5、汽车刹车作匀减速直线运动,3秒停止,刹车后1秒内,2秒内,3秒内的位移比—9:4:1—
6、一列火车由静止从火车站出发作匀加速运动,以位观察者站在这列火车第一节车厢的前端,经过2s,第一节全部通过观察者所在位置,全部车厢从他身边通过历时6s,设各节车厢长度相等,且不计车厢间距离,则这列火车个共有—9—节车厢,最后2s内从他身边通过的车厢有_5_节,最后一节通过观察者需要的时间是—0.27—s.
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