The first four steps in the formation of the sun are listed below.
1. a cloud of gas and dust called nebula spins slowly.
2. the nebula collapse due to condensation of gases
3. the cloud spins faster as it collapses.
4. the contracting nebula flattens into a disk with a bulge at the center
which of these statements bet describe the next step in the formation of the sun?
a. gravitational forces pull the gases further away from the center of the disk.
b. nuclear fusion of gases takes place in the center of the nebula.
c. the gas particles in the center of the nebula repel each other and move apart
d. the nuclear fission of the gas molecule releases large amount of energy

In a steady-flow steam power plant system, two adiabatic high-pressure and low-pressure turbines ane used to generate power. superheated steam enters the high-pressure turbine at 8 mpa and 550°c. the steam expands in the high-pressure turbine to a saturated vapor at 3 mpa. in order to increase the powe generation of the power plant, another steam turbine working in a lower pressure ranges is deployed. the outlet vapor from the first turbine is heated up at a boiler to the temperature of 500 c at the constant pressure of first turbine's outlet (3 mpa). then, the vapor enters the second turbine and produces extra work. the exit conditions of the second turbine are 5o kpa and 90 percent quality. if the total power output of the power plant is 25 mw, determine a) the mass flow rate of the water (kg/s). b) heat transfer rate in the boiler (mw). (30 points) 3 mpa 00 c 8 mpa s0 c high pres turbine low pres boiler turbine 50 kpa 3 mpa 09 saturated vapor t heat engine, shown in the figure, operates between high temperature and low temperature of through a heat 4. a carnot tn and tu respectively. this heat engine receives energy from a heat reservoir at t exchanger where the heat transferred is proportional to the temperature difference as ? = k (z,-7, ). it rejects heat at a given low temperature tl. to design the heat engine for maximum work output, find the high temperature, th, as a function of tes and t. (15 points) qe

In the 1980's, congress authorized the u.s. department of energy to build the wipp facility in the chicuahuan desert in new mexico. what is the purpose of wipp?

World class speed skaters can skate a 3,000-m course in about 4 minutes.what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s