题目

听下面一段独白，回答以下小题。【1】What did Shakespeare do during his school years?A.He read a lot of books.B.He worked hard at French grammar.C.He learned many foreign languages.【2】Why did Shakespeare leave school?A.Because he married a farmer's daughter.B.Because he had to help support his family.C.Because he didn't get along well with his classmates.【3】When did Shakespeare start to write plays?A.At the age of seven.B.After he became an actor.C.As soon as he arrived in London.【4】What do we know about Shakespeare?A.He had a very happy family.B.He received very goo两根粗糙的金属导轨平行放置在倾角为θ=30°的斜面上，导轨左端接有电阻R=10Ω，导轨自身电阻忽略不计．匀强磁场垂直于斜面向上，磁感强度B=0.5T．质量为m=0.1kg，电阻可不计的金属棒ab静止释放，沿导轨下滑．如图所示，设导轨足够长，导轨宽度L=2m，金属棒ab下滑过程中始终与导轨接触良好，当金属棒下滑h=3m时，速度恰好达到最大值v=2m/s．求：（1）下降h过程中，电阻R的最大热功率为多大；（2）静止释放时的加速度；（3）此过程中电阻中产生的热量．