We _____ your visit ever since you sent us an email informing us your date of arrival. A. expected B. are expecting C. have been expecting D. have been expected 答案:C
如图所示,长为L,倾角为的光滑绝缘斜面处于水平向右的匀强电场中.一电荷量为+q,质量为m的小球,以初速度v0由斜面底端的M点沿斜面上滑,到达斜面顶端N的速度仍为v0则:
A.
小球在N点的电势能小于在M点的电势能
B.
M、N两点的电势差为mgL/q
C.
电场强度等于mgtan/q
D.
电强强度等于mgsin/q