A steel rail way track in kaduna has a length of 27m when the temperature is 35°c. a. what is the length on the 3rd day when temperature is 44°c
b. suppose the truck is held firmly to the ground so that it can expand 10 at stress results in the track due to the temperature change take young modulus of Steel is 2.0 x 10¹¹ and 1m² of linear expansion Steel as 1.1×10`³⁰c

Heat from the sun reaches earth to a. radiation b. convection c. conduction

Ascrew incorporates which other simple machine? lever wheel and axle inclined plane pulley

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