一质量为2kg的物体沿水平面向右做直线运动,t=0时刻开始始终受到一个水平向左的恒力F,如图甲所示,取水平向右为正方向,物体的v﹣t图象如图乙所示,g=10m/s2 , 则() A . 恒力F的大小为3N B . 10s内恒力F对物体做功102J C . 10s末物体在计时起点位置左侧2m处 D . 10s内物体克服摩擦力做功2J 答案:A,CIn 1903 Marie was given the Nobel Prize for her research. In 1911 she
received _____one, _____ person in the world to receive two Nobel Prizes.
A.
a second; first B. second;
first
C.
a second; the first D. the
second; the first