Physics, 07.04.2020 03:21 laqu33n021
Many caterpillars construct cocoons from silk, one of the strongest naturally occurring materials known. Each thread is typically 2.0 μm in diameter and the silk has a Young's modulus of
4.0 ✕ 109 N/m2.
(a) How many strands would be needed to make a rope 11 m long that would stretch only 1.00 cm when supporting a pair of 85-kgmountain climbers?
✕ 106 strands
(b) Assuming that there is no appreciable space between the parallel strands, what would be the diameter of the rope?
Answers: 3
Physics, 22.06.2019 00:30
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
Answers: 2
Physics, 22.06.2019 14:30
What distance does a car travel as its speed changes from 0 to 20 m/s in 17 s at constant acceleration?
Answers: 1
Physics, 22.06.2019 23:30
The power exerted by a muscle is the product of the force exerted and the velocity of contraction. the area of which of these shaded regions represents the power exerted while a weight is lifted at maximum speed?
Answers: 2
Many caterpillars construct cocoons from silk, one of the strongest naturally occurring materials kn...
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