One possible cause of gamma-ray bursts is collisions between comets in the oort cloud. imagine that two comets collide head-on. each is a spherical ball of ice, of radius 1km and density 1000 kg/m3 , travelling at 100 m/s. if the collision happens at a distance of 1000 au from the earth, and 1% of the collision energy is released as radiation, what fluence would you measure at the earth?

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.