回复：一道难题

Fill the upper glass with water first --- so that the bottom of the glass closely attaches to the coin's surface (assume the coin's surface is smooth neough).
Then fill the gap between the upper glass and lower one, use the empty pen pipe to suck out the water in the upper glass gradually, do this until the upper glass is floating to the top the lower one, the coin should be sticked to the bottom of the upper glass and thus got out.

所有跟帖： 

• 不是了，不能用水了。。。。 -quyuanfang- ♀ (0 bytes) () 08/17/2004 postreply 11:04:25

• the problem did not say that:) -idiot94- ♂ (0 bytes) () 08/18/2004 postreply 06:55:13

• 我认为你做不到! -只取一杯羹- ♀ (84 bytes) () 08/22/2004 postreply 17:49:02