I like football very much.I want a football player. [ ]
A.is
B.am
C.to be
D.be
答案:C
弹簧振子做简谐运动时,以下说法正确的是( )
A.振子通过平衡位置时,回复力一定为零
B.振子做减速运动时,加速度却在增大
C.振子向平衡位置运动时,加速度方向与速度方向相反
D.振子远离平衡位置运动时,加速度方向与速度方向相反