题目

The chart shows how long the students in Class Three do these sports. It takes them three hours to do all the sports. So they spendminutes playing soccer. Kung fuJoggingHikingThai ChiPlaying soccer 10％25％30％20％? A . 27 B . 34 C . 15 答案：A一物体的位移函数式是s=4t+2t2+5（m），那么它的初速度和加速度分别是（ ）A．2m/s，0.4m/s2B．4m/s，2m/s2C．4m/s，4m/s2D．4m/s，1m/s2