驼峰专用无源型车轮传感器适应的车速范围为()。
A:3~30km/h B:0~30km/h C:3~50kmh D:0~60km/h
观察下列图形,根据提供信息填空;
△DGO≌△
△ATQ≌△
△RBE≌△
△KMH≌△
(1)观察△ODG和△ART可知D、G、O的对应点分别为R、T、A,故填:RTA;
(2)观察△ATQ和△OCM可知A、T、Q的对应点分别为M、C、O,故填:MCO;
(3)观察△BRE和△BGE可知R、B、E的对应点分别为G、B、E,故填:GBE;
(4)观察△KMH和△KDH可知K、M、H的对应点分别为H、D、K,故填:HDK;
某单位鼓励职工节约用电.规定每月职工用电收费标准为20kwh以内按0.2元/kmh计算,超过20的按0.50元/kmh计算.现已知某职工某月用电15kmh,那么他这个月应该交费多少钱?另一位职工因为经常忘记关电脑,用电量达到28kmh,那么他应该交多少电费?
解:0.2×15=3(元)
0.2×20+0.5×(28﹣20)
=4+0.5×8
=4+4
=8(元)
答:某职工某月用电15kmh,他这个月应该交费3元钱;另一位职工因为经常忘记关电脑,用电量达到28kmh,他应该交8元电费.
一辆沿着平直公路行驶的汽车,它的速度在5s内从43.2km/h增加到64.8km/h,通过的路程是70m,则这辆车在5s内的平均速度为( )
A:50.4km/h B:54kmh C:21.6kmh D:36km/h
我国自制的最大水陆两栖飞机AG600在广州珠海首飞成功,AG600可以在地面或水上起飞和降落,最大巡航速度为500kmh,飞机空载质量为41.5吨,20秒内可一次蓄满水12吨,主要用于大型灭火和水上救援.某次灭火演习中,空载的AG600在水面漂浮时所受浮力为 N,蓄满水后加速起飞,飞向演习火场上空过程中飞机的重力势能 (“增大”、“减小”或“不变”).

解:(1)空载的AG600时的重力:G=mg=41.5×103kg×10N/kg=4.15×105N;
空载的AG600在水面漂浮,根据漂浮条件可知其受到的浮力:F浮=G=4.15×105N;
(2)当蓄满水后加速起飞,飞向演习火场上空过程中,由于飞机的质量不变,高度增加,则飞机的重力势能增大.
故答案为:4.15×105;增大.
已知A,B两地相距240km,甲车先从A地出发30min后,乙车从B地出发,相向而行,甲车全程以80km/h的速度行驶,乙车以90km/h的速度行驶1h后,再以75kmh的速度驶完剩余路程,下列选项中能正确反映甲、乙两车距A地的距离y(km)与甲车行驶时间x(h)函数关系的图象是( )
A:
B:
C:
D:
有关部门规定在一般公路上正常行驶的汽车速度不能超过80kmh.某一在平直路面上以72km/h速度匀速行驶的汽车,刹车后做匀减速直线运动,经过4s速度减小为36kmh,求:
(1)刹车后5s末汽车的速度大小;
(2)刹车后10s内汽车的位移大小,
解:(1)速度v1=72km/h=20m/s,v2=36km/h=10m/s,
根据加速度定义可知:a=[8f366c4017929d54.png]=﹣2.5m/s2,汽车的加速度为﹣2.5m/s2与汽车运动方向相反;
汽车做匀减速直线运动,速度减为0的时间为:t0=[8845db0963be1869.png]=[5871b138c5a1c77a.png]=8s
汽车5s末的速度大小为:v=v1+at2═20﹣2.5×5=7.5m/s;
(2)因10>t0=8s,则可由速度位移公式得:x=[a2f166314bb43447.png]=[2b53821667f6699e.png]=80m;
答:(1)刹车后汽车6s末的速度大小为7.5m/s;
(2)刹车后汽车10s内的位移大小为80m
A:全长66km属于位移
B:起点速度95kmh属于瞬时速度
C:该汽车全程的平均速度是92.5km/h
D:该汽车没有超速
火车从A站驶往B站,途中经过一铁路桥,若火车过桥最高限速为72kmh,火车减速前的速度为288km/h,火车减速行驶30s,恰好以最高限速通过铁路桥,火车减速过程中的加速度大小为( )
A:0.5m/s2 B:1m/s2 C:2m/s2 D:7.2m/s2
阅读理解;阅读下面的短文,从每小题所给的A.、B.、C.、D.四个选项中,选出最佳选项。
Time zone:
Eastern Standard Time(EST): GMT+ 10 hours.
There is no daylight saving time in QueenslanD.
Legal drinking age:
18 years and older. Always keep your ID with you to prove your agE.
Alcohol (酒) shops & hotels are the only places where alcohol can be bought.
Dangers:
Dial 000 from a fixed line or 112 from a mobile phonE. Police, ambulance, firE.
Electricity:
240/250 volts AC 50Hz Universal outlets for 110 volts (shavers only) standard in hotels, apartments, motels.
Telephones:
Australian international code is 61.
Road rules:
Left hand side driving. There is a 50kmh speed limit in most living areas and on open highways100-110kmh. Seat belts must be worn all the timE. If you want to hire a car, take along your driver's licensE.
No smoking:
Indoors: Indoor areas are no smoking.
Poker Machines: Poker machine areas are no smoking.
Outdoors: Non-enclosed eating and drinking areas are no smoking.
Swimming Safety:
ALWAYS SWIM BETWEEN THE RED AND YELLOW FLAGS and pay attention to the life guards' advicE. Gold Coast beaches are guarded by skilled life guards and volunteers at weekends.
1. The above information is most probably taken from a (an) _____.
A. science magazine B. education newspaper
C. travel guidebook D. horror novel
2. We can learn from the above information that in Queensland _____.
A. smoking is not allowed in lots of places
B. people can buy alcohol anywhere with ID
C. people can swim beyond the red and yellow flags
D. when a building is on fire, dial 112 from a fixed line
3. If Mr Black is having a holiday in Queensland, he can _____.
A. drive on the right hand side
B. hire a car with his driver's license
C. drive at the speed of 120kmh on highways
D. drive his car without wearing the seat belt
1C 2A 3B