• How much does evolution affect humans?

    How much does evolution affect humans?

    The race deniers have lost a lot of battles. When anthropologists discovered africans and non-africans have been separated for 70,000 years it was a pretty big blow. Before that they said skin color changed over the course of around 10,000 years. Only it was 70,000. That would've been bad in and of itself, but... show more
    The race deniers have lost a lot of battles. When anthropologists discovered africans and non-africans have been separated for 70,000 years it was a pretty big blow. Before that they said skin color changed over the course of around 10,000 years. Only it was 70,000. That would've been bad in and of itself, but it became worse around 2007 when geneticists were able to sequence the human genome. And the first thing they found were different homologous clusters of DNA among different races. Now ancestry tests can tell you your exact race down to .01 of a percent. This one really hurt, because before there was "no biological basis in race, because I don't know what categories are, or the difference between coding and non-coding sequences are" - said the race deniers. But once we can accept that yes, evolution works in humans. Divergent evolution happened between polar bears and grizzly bears 70,000 years ago, which is almost the exact same duration non-africans & Africans have been geographically apart, until like the past 500 years or so. Now we're learning other languages and becoming more globalized, but before then they were more or less entirely separated groups. & if sociology is any guide, then Africans are not the most intelligent. Perhaps it's because of them evolving in a tropic biome for so long, which makes athleticism a much more important trait for natural pressures. In temperate biomes, alleles and genes linked to intelligence become more concentrated in that pop.
    31 answers · Biology · 2 days ago
  • If the Earth is round, why don't airplanes have to compensate for the curvature of the Earth?
  • Suppose a ball is thrown straight up into the air, and the height of the ball above the ground is given by the function? PLeaseee?

    Best answer: h(t) = -16t^2 + v₀t + h₀ Where: h = the height of the object at any given point in time (in ft) t = time the object is in motion (in sec) h₀ = the initial height (in ft) v₀ = the initial velocity (in ft/sec) If v₀ < 0, the object was propelled downward v₀ = 0, the ball was dropped from rest with no... show more
    Best answer: h(t) = -16t^2 + v₀t + h₀

    Where:

    h = the height of the object at any given point in time (in ft)
    t = time the object is in motion (in sec)
    h₀ = the initial height (in ft)
    v₀ = the initial velocity (in ft/sec)
    If v₀ < 0, the object was propelled downward
    v₀ = 0, the ball was dropped from rest with no initial velocity
    v₀ > 0, the ball was propelled upward

    So in this case we have:

    h(t) = -16t^2 + 37t + 6

    v₀ = 37 ft/sec
    h₀ = 6 ft

    The first derivative of position, h(t) in this case is the velocity:

    v(t) = dh/dt = -32t + 37

    v(3.2) = -32 * 3.2 + 37 = - 65.4 ft/sec => the negative sign is the direction of velocity which is downward

    The above makes D) => the correct choice

    however he ball will hit the ground when the height is zero we can find the time that takes place:

    -16t^2 + 37t + 6 = 0
    using the quadratic formula the approximated times are:
    t ≈ - 0.15 , 2.5 sec => disregarding the negative time, thus the ball hits the ground at t = 2.5 sec, which means at t = 3.2 sec, the ball should be resting on the ground so there is either an error or we are missing some more information
    6 answers · Mathematics · 12 hours ago
  • Does our sun have a name?

    Best answer: The official name, in English, of our star is Sun (with a capital S). The word "sun" (small s) is a simile: a word used to describe things that are similar. Other stars that have planets are often called suns (small s), but in astronomy, we try to avoid the simile unless it is quite clear. Our Sun's... show more
    Best answer: The official name, in English, of our star is Sun (with a capital S). The word "sun" (small s) is a simile: a word used to describe things that are similar. Other stars that have planets are often called suns (small s), but in astronomy, we try to avoid the simile unless it is quite clear.
    Our Sun's name, in Latin, is Sol. That is why we have the adjective solar, in English.
    The Solar system (the system of planets around "Sol") is OUR planetary system. Other planetary planets (around other stars) are not solar systems (they are planetary systems or systems of planets).
    The name of our Sun in Greek is Helios. That is why we talk of the heliographic system (the system describing the Sun as the centre).

    The official name, in English, for our natural satellite is Moon (capital M). The word moon (small m) can be used as a simile for other objects that are similar. For example, the moons of Jupiter. However, in astronomy, the official word for these things is "satellite".
    Moon's name in Latin is Luna; we have the adjective lunar, in English.

    Our Galaxy's official name in English is (was) Galaxy - with a capital G. Other galaxies are given names that depend on the direction in which we see them from Earth (the Andromeda galaxy appears to be in the constellation called Andromeda), or on the shape of the galaxy (the Sombrero galaxy looks like... a sombrero), or the number it has in some official list (for example NGC-224, for the 224th galaxy listed in the New General Catalogue).
    The Milky Way is a band of stars that makes up a part of our Galaxy. Calling our Galaxy the Milky Way galaxy (with or without a big G) is not wrong, but it is redundant (the word galaxy comes from a Greek word meaning "milky").

    The problems started when an American astronomy magazine asked authors to use lower-case letters for the proper names of the Sun and the Moon, giving people the false impression that these things had no names.
    17 answers · Astronomy & Space · 3 days ago
  • Are ufo;s for real?

    19 answers · Astronomy & Space · 2 days ago
  • How about we shove Jupiter into Neptune?

    So we have more room to get to Mars.
    So we have more room to get to Mars.
    15 answers · Caceres · 1 day ago
  • A rubber ball is dropped from the top of a hole. Exactly 1.5 seconds​ later, it's heard hitting the bottom. How deep is the hole​?

    Best answer: The speed of sound in air is 343 m/s. During the first part of 1.5 seconds, the ball falls from the top to the bottom of the hole. During the second part of 1.5 second part of the 1.5 seconds, the sound rises from the bottom to the top of hole. Let t be the time the ball is falling and 1.5 – t be the time the sound... show more
    Best answer: The speed of sound in air is 343 m/s. During the first part of 1.5 seconds, the ball falls from the top to the bottom of the hole. During the second part of 1.5 second part of the 1.5 seconds, the sound rises from the bottom to the top of hole. Let t be the time the ball is falling and 1.5 – t be the time the sound is rising.

    For the ball, d = ½ * 9.8 * t^2 = 4.9 * t^2
    For sound, d = 343 * (1.5 – t) = 514.5 – 343 * t
    These two distances are equal.

    4.9 * t^2 = 514.5 – 343 * t
    4.9 * t^2 + 343 * t – 514.5 = 0
    t = [-343 ± √(343^2 – 4 * 4.9 * -514.5)] ÷ 9.8
    t = [-343 ± √127,733.2] ÷ 9.8
    t = [-343 + √127,733.2] ÷ 9.8

    The time is approximately 1.47 seconds.

    For the ball, d = 4.9 * (343 + √127,733.2] ÷ 9.8)^2
    The distance is approximately 10.6 meters.

    OR

    d = 514.5 – 343 * (-343 + √127,733.2] ÷ 9.8)
    The distance is approximately 10.6 meters.
    6 answers · Physics · 2 days ago
  • Did Darwin disprove the myth of extinction?

    Species don't go extinct, they evolve.
    Species don't go extinct, they evolve.
    18 answers · Biology · 2 days ago
  • Is marijuana vegan?

    15 answers · Botany · 2 days ago
  • How many yards = .3 miles?

    14 answers · Mathematics · 2 days ago
  • Is it possible that our galaxy is at the center of the Universe?

    Best answer: The Hubble Telescope has proved it isn't.
    Best answer: The Hubble Telescope has proved it isn't.
    25 answers · Astronomy & Space · 4 days ago
  • What’s in Kyrgyzstan?

    10 answers · Geography · 23 hours ago
  • (4-x)/(x-5) > 1/(1-x)?

    Best answer: (4 - x)/(x - 5) > 1/(1 - x) (4 - x)(1 - x) > x - 5 4 - 5x + x^2 > x - 5 x^2 - 6x + 9 > 0 (x - 3)^2 > 0 ---> x =/= 3. Not done yet; x = 1 (excluded value) x = 4 (a zero on the left side), and x = 5 (excluded value) must be used for interval bounds. If x < 1, you have plus/minus > 1/plus... show more
    Best answer: (4 - x)/(x - 5) > 1/(1 - x)

    (4 - x)(1 - x) > x - 5

    4 - 5x + x^2 > x - 5

    x^2 - 6x + 9 > 0

    (x - 3)^2 > 0 ---> x =/= 3.

    Not done yet; x = 1 (excluded value) x = 4 (a zero on the left side), and x = 5 (excluded value) must be used for interval bounds.

    If x < 1, you have plus/minus > 1/plus ---> minus > plus. Doesn't work.

    If 1 < x < 3, you have plus/minus > 1/minus ---> minus > minus. Doable.

    If 3 < x < 4, the same happens as in the previous case (minus > minus). Doable.

    If 4 < x < 5, you have minus/minus > 1/minus ---> plus > minus. This works.

    If x > 5, you have minus/plus > 1/minus ---> minus > minus. But this fails because you have a number increasing toward -1 that is greater than a negative unit fraction -- a false statement because the negative unit fraction is closer to 0.

    Solution interval union should be (1, 3) U (3, 5); 1 < x < 3 or 3 < x < 5 should satisfy the inequality.
    7 answers · Mathematics · 3 days ago