A typical carbon dioxide tank for a paintball gun holds about 12 oz of liquidCO2The tank is filled no more than one-third with liquid, which, at room temperature, maintains the gaseous phase at about 850 psia. (a) If a valve is opened that simulates a converging nozzle with an exit diameter of 0.050 in, what mass flow and exit velocity results? (b) Repeat the calculations for helium.

337J/kg

Explanation:

(a) For air, take  k = 1.40, R = 287 J/kg ⋅ K, and cp = 1005 J/kg ⋅K. The adiabatic steady-flow energy equation (9.23) is used to compute the downstream velocity:+ = = + = +2 2 2p 21 1 1c T V constant 1005( 260) (75) 1005(207) V or .2 2 2

Ans2mV 335 s≈2 1 p 2 1 2 1 207 273 30Meanwhile, s s c ln(T /T ) R ln( p /p ) 1005 ln 287 ln ,260 273 140+   − = − = − ÷  ÷   +or s 2 − s1 = −105 + 442 ≈ 337 J/kg ⋅ K Ans.(a)

(b) For argon, take k = 1.67, R = 208 J/kg ⋅ K, and cp = 518 J/kg ⋅ K. Repeat part (a):2 2 2p 21 1 1c T V 518(260) (75) 518(207) V , solve .2 2 2 Ans+ = + = + 2mV 246 1 207 273 30s s 518 l n 208 ln 54 320 . (b)260 273 140

the correct answer is c.stops after infancy and childhood.

myelin is the substance of the central nervous system (cns) that insulates nerve cell axons to increase the speed at which nerve impulse travels. myelination is a process of myelin formation. this process occurs postnatally, begins in the embryo during the midst of early development and finishes after birth.