问题
选择题
—___do you celebrate Chinese New Year?
—We celebrate it by giving presents and red packets.[ ]
A. Where
B. What
C. How
D. Why
答案
答案：C
搜题请搜索小程序“爱下问搜题”
—___do you celebrate Chinese New Year?
—We celebrate it by giving presents and red packets.[ ]
A. Where
B. What
C. How
D. Why
答案：C
，接着沿直线BC（此处无轨道）运动到达C处进入半圆轨道，进入时无动能损失，且刚好到达D点，从D点飞出时磁场消失，不计空气阻力，g＝10m/s2，cos37°＝0.8，求：