Well, if I was targetting modern, western MBTs or t-90s, I'd probably move up to 40 pound mini-anvils. <img src="/images/graemlins/smile.gif" alt="" />

Force = mass*acceleration.

Assuming release altitude of around angels 20, 23ft/sec^2 acceleration, with a 40lbs mass equals.... wow, I never thought I'd use calculus like this..... A big honking hole in the roof of a tank. <img src="/images/graemlins/smile.gif" alt="" />

But yeah, a tactical team with a trained and geared up liger is scarier.

Edit: OK, it is a LOT of energy. My computer and calculators all agree, we are talking about something in the area of 1.7x10^9 tons of energy. That equation does NOT take into account drag and resistance, however, so that number assumes constant, infinate acceleration, rather than reaching a finite terminal velocity. If anyone is enough of a geek to check my numbers... diff((40*32)/(x^2))dy/dx, from 0 to 20000, using pounds, feet and seconds (x).