一列火车做匀变速直线运动驶来,一人在火车旁观察火车的运动,发现相邻的两个10s内,列车从他跟前驶过8节车厢和6节车厢,每节车厢长8m,求:(1)火车的加速度(2)人开始观察时火车的速度大小。 答案:(1)a=-0.16m/s2 (2)v=7.2m/s19、I am very grateful to my high school teachers,
without ________help I wouldn’t be so excellent.
A.
whom B.
them
C.
which
D. whose