—Can you sing?
—_____ [ ]
A. Yes, I do
B. No, you can't
C. Yes, I can
D. Yes, I am
答案:C
金属杆a b水平放置在某高处,当它被平抛进入方向坚直向上的匀强磁场中时(如图所示),以下说法中正确的是
A.运动过程中感应电动势大小不变,且Ua>Ub
B.运动过程中感应电动势大小不变,且Ua<Ub
C.由于速率不断增大,所以感应电动势不断变大,且Ua>Ub
D.由于速率不断增大,所以感应电动势不断变大,且Ua<Ub
1,7,20,44,81,()
A.135
B.168
C.173
D.196