我说一下算法:
子弹射穿A的过程整体动量守恒m0v0=m0v+(MA+MB)V1
子弹进入B至最后,A匀速,子弹与B动量守恒mov+MBV1=(m+MB)V2
平抛运动知识可知两物体平抛初速度之比为V1:V2=1:2
联立可得v= V1= V2=
ΔE1=1/2m0v0^2-1/2m0v^2-1/2(MA+MB)V1^2
ΔE2=1/2mov^2+1/2MBV1^2-1/2(m+MB)V2^2
Substantial stakes for NBC in fall Television time
The brand that dominated Tv for 20 decades commencing while in the mid-1980s with smash hits like "The Cosby Demonstrate," then "Friends" and "Seinfeld" has spent the last 6 years caught in last place as its managers pursued what they believed was a forward-looking technique aimed at cutting expenses. Now the network has a new proprietor ?a cable large Comcast ?a plus a much-admired new programmer ?a Bob Greenblatt, previously of Showtime ?a who're bent on restoring the luster of a network that when set criteria for both quality and ratings in prime time.
With Greenblatt at the helm,wholesale nike air shox, the network is wanting to lure precisely the same upscale,wholesaler, educated younger audience it once had a lock on. NBC has ordered "Smash," a musical comedy set on Broadway, which is earning comparisons with Fox's hit "Glee," that stars Debra Messing and Anjelica Huston and is also created by Steven Spielberg. Additionally, it picked up "Prime Suspect," an update of the stylish British detective sequence with Helen Mirren that ran on PBS (Maria Bello will perform the lead), also as comedies with Christina Applegate and Whitney Cummings.
The stakes could not be increased: In accordance to study firm SNL Kagan, NBC,wholesalers, a one-time cash cow, lost almost $81 million in 2010, compared with a $14-million earnings the past 12 months as well as a $204-million profit in 2008 (the knowledge incorporate only outcomes from network operations, not company-owned and ?§Coperated neighborhood Tv stations). Now analysts and talent representatives are hailing NBC ?a which will be the first network to greet advertisers Monday early morning ?a to get a return to kind.