Models of the first star-forming clouds indicate that they had a temperature of roughly 180 k and a particle density of roughly 3.50×105 particles per cubic centimeter at the time they started trapping their internal thermal energy.

part a: estimate the mass at which thermal pressure balances gravity for these values of pressure and temperature.

part b: how does that mass compare with the sun's mass?

part c:

what is the estimated lifetime of a star with that mass?

choose the answer that best fits your estimate

greater than 10 million years
less than 10 million years
about 10 billion years
about 1000 years

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Which types of electromagnetic waves have higher frequencies than the waves that make up ultraviolet light? check all that apply. radio waves infrared light microwaves gamma rays visible light x-rays

Acompound machine is also called a machine. a. force b. simple c. complex d. directional