从离地面80m的高空中自由下落一个小球,求:自开始下落时计时,小球在最后1s内的位移是多少?(取g=10m/s2)
It's a snowy day. Let's make a snowman. Let's make a big snowball for his ____, and a small snowball for his ____. Let's draw his ____. Let's put two sticks for his ____. Let's put a hat on him. I ____ he's wonderful!
A
B
成本(元/条)
50
35
利润(元/条)
20
15
若a和b互为相反数,则a+b的值为( )