There is a naturally occurring vertical electric field near the Earth’s surface that points toward the ground. In fair weather conditions, in an open field, the strength of this electric field is 110.0 N/C 110.0 N/C . A spherical pollen grain with a radius of 11.0 μm 11.0 μm is released from its parent plant by a light breeze, giving it a net charge of − 0.550 fC −0.550 fC (where 1 fC = 1 × 10 − 15 C 1 fC=1×10−15 C ). What is the ratio of the magnitudes of the electric force to the gravitational force, F e l e c t r i c / F g r a v Felectric/Fgrav , acting on the pollen? Pollen is primarily water, so assume that its volume mass density is 1000 k g / m 3 1000 kg/m3 , identical to the volume mass density of water.

6–55 refrigerant-134a enters the condenser of a residential heat pump at 800 kpa and 358c at a rate of 0.018 kg/s and leaves at 800 kpa as a saturated liquid. if the compressor consumes 1.2 kw of power, determine (a) the cop of the heat pump and (b) the rate of heat absorption from the outside air.

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

You are about to open a container of soy milk but notice that there are instructions to “shake well before serving.” the soy milk is most likely a