一质点沿直线运动的速度v随时间t变化的图线如图所示,则该质点的位移x(从t=0开始)随时间t变化的图线为哪一个?( )
A:
B:
C:
D:
——During the APEC summit(峰会),Beijing's sky was so blue and clear.——It APEC blue.But too bad it no longer stays that way.
2×( )<15____
( )×7<36____
( )×7<22____
6×( )<43____