如图所示是一物体做匀变速直线运动的v-t图象，由图可知物体（ ）
A．初速度为0
B．2s末的速度大小为3.0m/s
C．前2s内的位移为8 m
D．加速度大小为1.0m/s
A、由图知，T=0时刻物体的速度为5m/s，即初速度为5m/s．故A错误．
B、2s末物体的速度大小为3m/s．故B正确．
C、根据速度图象与坐标所围“面积”的大小等于位移，由几何知识得：前2s内物体的位移为x=
×2m=8m．故C正确．5+3 2
D、物体的加速度为a=
=△v △t
m/s2=-1m/s2，即加速度大小为1m/s2．故D正确．0-5 5
故选BCD
| 单词拼写。 |
| 1.He came to a p in reading and then went on reading. 2.How was it that she could t_____such noise? 3.Heavy rain p the possibility of continuing the game. 4.A wage rise of 5% represents an a increase of 250 for the lowest paid workers. 5.Hong Kong is very proud and p to host her significant event. 6.Next Tuesday is the (截止日期) for sending in your application. 7.As a leader,it’s wrong to (滥用) the power at any time. .The robbers tried to (抢劫) me of the bike but a policeman saved me. 9.The doctor told her to watch out for (症状) of measles . 10.We should have (预见) this trouble months ago and made provisions for it. |