Consider a freely spinning merry-go-round, which can be treated as a uniform disc of radius R and mass m1 rotating about a vertical axis through its center. Initially the merrygo-round is at rest. A boy of mass m2 jumps with a horizontal speed v, landing at A, which is a distance R 4 from the center. Hint: Neglect the vertical fall of the boy. m , v m R/4 O A R 1 2 As the boy is approaching the merry-goround, what is the magnitude of his initial angular momentum with respect to the center of the merry-go-round

Which instrument is used to measure air temperature

Research the neutrino using the internet and report your findings. in a nuclear decay, the nucleus of an atom splits apart. larger particles can be detected and their masses and velocities can be recorded. explain how the existence and properties of the neutrino could be predicted using the conservation laws.

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