Suppose that 2 j of work is needed to stretch a spring from its natural length of 36 cm to a length of 52 cm. (a) how much work is needed to stretch the spring from 44 cm to 48 cm? (round your answer to two decimal places.) j (b) how far beyond its natural length will a force of 15 n keep the spring stretched? (round your answer one decimal place.) cm

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

Which of the following compounds would be primarily ionic? methane, ch4, ammonia nh3, calcium chloride, cacl2, or carbon dioxide, co2

The index of refraction of the oil is 1.20. what is the minimum thickness t of the oil slick at that spot?