Astronomers suspect that a galaxy’s type can be affected both by the conditions in the protogalactic cloud from which it forms ("initial conditions") and by later interactions with other galaxies. each item below describes either a condition in a protogalactic cloud or a later interaction. match these items to the galaxy type you would expect to form as a result. spiral galaxy or elliptical galaxy? 1. protogalactic cloud has high angular momentum2. a galaxy collision strips away gas3. protogalactic cloud rotates very slowly4. most protogalactic gas settles into a disk5. protogalactic cloud has high density6. stars form rapidly as the protogalactic cloud shrinks

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.