2022英语周报八年级新目标上册答案

传送带的电机因传送物块额外消耗的电能最少,所以有W=12mx+Q(1分)解得Wm=2(2-√2)mgs(1分)15【解析】(1)传送带静止时由能量守恒定律可知E=Amgs(1分)物块在传送带上时传送带一直对物块做正功,则物块一直处于加速状态,设物块到传送带左端时速度为根据功能关系有pmg=2mt2-E,(1分)解得v=2即传送带的速度至少为2√pgs(1分)(2)设物块滑上传送带时的初速度为w,则2m=E(1分)解得v=√2gpA5物块在传送带上运动的加速度a=gH(1分)在传送带上运动的时间=V=(2-(1分)物块与传送带间产生的热量为Q=pmg(vt-s)(1分)传送带速度取最小值功=v(1分)

第二节One possible versionDear Mr. TomIm writing to invite you to be present at the recitationcontest organized by the reading club at 3: 00 next Wednes-day afternoon in the lecture hall. If available then. couldyou do us a favor? And we would appreciate having you as ajudge. By the way, it would be very nice if you can recommend some classic English literary works suitable for usstudentsanks for considering our requestIm looking forward to your reply at your earliest con-venience lYours sincerelyLi Hua

以上就是2022英语周报八年级新目标上册答案，更多英语周报答案请关注本网站。