题目

在冬天，高为h＝1.25m的平台上，覆盖一层薄冰，一乘雪橇的滑雪爱好者，从距平台边缘s＝24m处以一定的初速度向平台边缘滑去，如图所示，当他滑离平台即将着地时的瞬间，其速度方向与水平地面的夹角为θ＝45°，取重力加速度g＝10m/s2。求：   （1）滑雪者着地点到平台边 缘的水平距离是多大；   （2）若平台上的薄冰面与雪橇间的动摩擦因素为μ＝0.05，则滑雪者的初速度是多大？动词的适当形式填空Jim’s father1.(work) in a bank. He 2.(go) to work by bus every morning, sometimes he3. (ride) his bike. But he4. (be) never late for work. He 5.(work) very hard. Jim6.(like) his father very much. They often7.（play） badminton（羽毛球）in front of their house, sometimes they (play) table tennis in Jim’s school. Jim8.(like) to talk with his father. His father9.(like) to hear Jim talking about his friends and his school. On Saturday or Sunday, they often10.(play) on the computer. Jim 11.(have) many computer games. But he doesn’t 12.(play) them every day. He also 13.(work) hard at his lessons.