题型:判断题 如图所示,质量为4.0kg的物体在与水平方向成37º角、大小为20N的拉力F作用下,沿水平面由静止开始运动,物体与地面间动摩擦因数为0.20;取g=10m/s2,cos37º=0.8,sin37º=0.6;求:(1)物体的加速度大小;(2)经过2s撤去F,再经3s时物体的速度为多大? 查看答案
题型:判断题 ―I called you this morning, but nobody answered. ―I ______ the flowers in my garden at that time.[ ]A. watered B. was watering C. water 查看答案