1. The problem statement, all variables and given/known data Scientists at Brookhaven National Laboratory in New York in conjunction with Brooklyn Union Gas (now a division of Keyspan Energy) are developing a compressed helium projectile launcher called the RAPTOR (short for "rapid cutter of concrete"). The original technology behind the gas gun began in the 1980s as part of an anti-missile research program. Now instead of shooting down missiles in midair, the RAPTOR will be used to shoot tiny metal projectiles at the ground to cut concrete like a jackhammer. The device works by rapidly compressing helium gas from its storage tank pressure of 2 atmospheres to an unbelievable 1000 atmospheres in a fraction of a second. The resulting shock wave blasts the 1.8 g projectiles (about the same mass as a .22 caliber bullet) out the barrel of the gun at roughly 1600 m/s (more than twice the muzzle velocity of a high-powered rifle). The main benefit of this technology is that it is much quieter than conventional concrete cutters -- 85 dB for the RAPTOR compared to 125 dB for a jackhammer. The last reported prototype (RAPTOR III) was 2.0 m long, weighed 120 kg, and was able to split a 10 cm thick slab in seven shots. Determine … 1. the work done by the compressed helium on a projectile, 2. the average force of the compressed helium on a projectile, 3. the impulse delivered to a projectile, 4. the time a projectile spends in the barrel, 5. the recoil speed of the gun, 6. the height to which the gun would jump, and 7. the minimum energy needed to split the concrete slab. 2. Relevant equations W = Fd FΔt = mΔv (m1+m2)v = m1v1' + m2v2' F=ma 3. The attempt at a solution 1. w=Fd w=(120kg)(9.8m/s2)(2.0m) = 2352 J (is 9.8 the acceleration???) 2. F=ma F=(120kg)(9.8m/s2) = 1180 N 3. 1180N(Δt) = 120kg(1600 m/s) 4. Δt = F/mΔv 5. (0.0018kg + 120kg)(0m/s) = (0.0018kg)(1600m/s) + (120kg)(v2') -120kg(v2') = 2.88kgm/s v2' = -0.024 m/s 6. 7. I'm gonna try and work each of these out one at a time, so lets start with number 1! Or whichever the first one I got wrong is.