A force F~ = Fxˆı + Fyˆ acts on an object with Fx = 4 N and Fy = 6 N. The angle between F~ and the displacement vector ~s is 18◦ , and 106 J of work is done by F~ . Find the magnitude of ~s. Answer in units of m.

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 transition by an electron will release the greatest amount of energy? oa ob oc od

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.