Visitors to Britain may find the best place to sample local culture is in a traditional pub. But these friendly hostelries can be minefields of potential gaffes for the uninitiated.
An anthropologist and a team of researchers have (1) some of the arcane rituals of British pubs—starting with the (2) of getting a drink. Most pubs have no waiters—you (3) to go to the bar to buy drinks. A group of Italian youths (4) for 45 minutes before they realized they would have to (5) for their own. This may sound inconvenient, but there is a (6) purpose.
Pub culture is designed to (7) sociability in a society known for its reserve. Standing at the (8) for service allows you to chat with others (9) to be served. The bar counter is possibly the only (10) in the British Isles in which friendly conversation with (11) is considered entirely appropriate and really quite normal (12) . "If you haven’t been to a pub, you (13) been to Britain." This tip can be found in a (14) , Passport to the Pub: The Tourists’ Guide to Pub Etiquette, a (15) code of conduct for those wanting to sample "a central part of (16) life and culture". The trouble is that if you do not (17) the local rules, the experience may fall flat. For (18) , if you are in a big group, it is best if only one (19) two people go to buy the drinks. Nothing irritates the (20) customers and bar staff more than a gang of strangers blocking all access to the bar while they chat and dither about what to order.
圆弧槽相连，MO＝ON＝R。A物体与水平面间的摩擦力忽略不计，B物体与水平面间的动摩擦因数为0.5。开始时两物体静止。现让A物体以初速度
向左开始运动，设A与竖直墙壁、A与B均发生无机械能损失的碰撞。已知重力加速度为g。要使B物体第一次被A碰撞后，恰能上升至圆弧槽最高点P点，求：
V
