Chapters 7 and 8 24 Two identical clouds, radius 3 x 1016 m, temperature 10 K, collide with each other with relative velocity 4 km s- I. What is the time interval, tmn, over which each cloud falls into the shock? If the cooling rate in the shocked gas is Q : 1010,] slkg'1 decide whether the shock is approximately adiabatic or isothermal. If the clouds colliding produces an isothermal shock, what is the thickness of the shocked layer, X, at the moment that the entirety of each cloud has been shocked? At later times the layer relaxes into a structure that can be approximated by a hydrostatic isothermal slab, column density 0 1kg m'g. What fraction of the cloud masses remains within thickness x in this hydrostatic structure? (Ignore edge effects and variations of column density in the plane of the slab.)