题目

补全对话A:Do you know much about computers?B:A: I've just been reading an article about them.They are used for all sorts of things now. B:A:Yes, but they're used for other things too. Do you remember when we went to buyour tickets for the flight to Greece?B:A:The man asked where we wanted to go, and then he typed out the information on aform and waited for a reply. A few moments later he gave us our tickets. B: Of course. His machine must have beenconnected to a computer. A: A. For accounting systems andthings you mean?B. Not a great deal. C. That's right. D. No problem. E. Yes.如图所示为赛车场的一个水平“梨形”赛道，两个弯道分别为半径R=90m的大圆弧和r=40m的小圆弧，直道与弯道相切．大、小圆弧圆心O、O' 距离L=100m．赛车沿弯道路线行驶时，路面对轮胎的最大径向静摩擦力是赛车重力的2．25倍，假设赛车在直道上做匀变速直线运动，在弯道上做匀速圆周运动，要使赛车不打滑，绕赛道一圈时间最短（发动机功率足够大，重力加速度g=10m/s2，π=3．14）．则赛车（ ）A．通过小圆弧弯道的时间为5．85sB．在绕过小圆弧弯道后加速C．在大圆弧弯道上的速率为45m/sD．在直道上的加速度大小为5．63m/s2