A toddler with croup is given a vaponefrin updraft because of increasing respiratory distress. The nurse evaluates the treatment as being effective when see which of the following

A. The child’s color is normal.
B. The child’s retractions are less severe.
C. The child’s heart rate is 100 bpm.
D. The child’s pulse oximeter reads 90.

如图所示，质量为2kg的物体静止在水平地面上，物体与水平面间的动摩擦因数为0.25，现对物体施加一个大小为8 N、方向与水平方向成37 °角的斜向上的拉力，g取10m/s²，则物体在拉力作用后5s末的速度大小为_________m/s，撤去拉力后，物体还能滑行的最大距离为_________m。