Posts by Celaena

    1. Oahu has a total land area of 727 square miles. What percentage of Oahu is Maui knowing that Maui is 1546 km^2 total land area.

    1 square mile=2.59 square miles. 1546/2.59=596.9139 727/596.9139=1.2179

    2. In a pineapple, assuming it weighs 905g, the grams of sugar typically amount for 10% of its weight. A pineapple cut in chunk fills 4.5 cups. how many grams of sugar there is in one cup of pineapple chunk?

    1 cup= 128 x 4.5= 576 576/90.5=6.364

    3. A team won 80% of their payoff games, knowing that there were 10 games. In addition, they won 12 out of 15 of their regular season games. What is their total winning percentage?

    20/25 x 100=80%

    4. Let's assume that after a recent Hurricane, storm shutter production in Hawaii would be increased. If 4,000 storm shutters were sold in 2019, and demand increases by 45% every three years, how many were to be sold in 2022? 2030? 2050?

    2022: 4000 x 1.45= 5800 2030: 17683.025 2050: ? I think the formula to get to 2050 is 4000(1 +0.45)t but idk what t is.

    5. The price of coffee is increasing by 1 cents per ounce per week as a result of a shortage. If the price if $6.50 per pound today, what will it cost for a 12oz bag in 4 months?

    4 months= 17.381 weeks 6.50+17.381=28.881

    6. Suppose in one month currency 1 lost 5.3% of its value against currency 2. At this rate, approximately how long will it take for currency 1 to loose half of its value against currency 2?

    Thalf= 70/P 70/5.3= 13.2 months

    7. In 2000, the population of Littletown was 17,000. Use the given doubling time to predict the population in 2060. Assume a doubling time of 32 years.

    new value= initial value x 2t/tdouble (I don't know how to solve this but the answer is 62,400. Could someone show me how they would get that number)

    Thank you

    A simple theory of solar heating (or heat from the Sun) predicts that the temperature in K of a planet or other body will depend on the distance from the (AU) according to this equation: temperature = 300/square root distance

    Estimate the temperature of Oumuamua at its closest approach of 0.25 AU (perihelion) to the Sun.

    300/ square root 0.25 = 600 K

    Estimate the temperature of Oumuamua when it was in the Oort Cloud at approximately 100 AU.

    300/square root 100= 30 K

    I feel like this answer is wrong since the formula they gave me was to solve for the Suns distance.

    Thank you.

    Radioactive Dating

    A geologist finds a rock which contains 3 atoms of Argon for every 1 atom of Potassium. She assumes the rock had no Argon when it solidified because Argon is a gas even at normal temperatures and while it might be trapped in a bubble in the rock, it could not get trapped as isolated atoms in solid rock. Therefore, all the Argon came from the radioactive decay of Potassium. Potassium only decays into Argon, so she knows that that 3/4 of the Potassium has decayed into Argon and only 1/4 of the original Potassium is left. In each radioactive half-life, 1/2 of the atoms decay. If only 1/4 of the original Potassium is left, then two half lives (1/2 of 1/2) of Potassium have elapsed since the rock was formed. The geologist knows that Potassium has a half life of 1.3 billion years, so the rock the geologist found is 2.6 billion years old.

    Question 1. The geologist finds another rock that has seven Argon atoms for every Potassium atom, or 1/8 of the original Potassium. How old is this rock?

    Potassium^40 Argon^40 + e =1.3 billion years

    Avogadro's number tells us 6 x 10^23 atoms in a mole. One mole would produce 3,000,000 decays per second.

    Plate Tectonics

    Measurements using radio telescopes and satellites show that Europe and North America are moving apart by about 4 cm per year because of plate tectonics.

    Question 2. How old would the oldest rocks on Earth be if the entire crust was created by the rift zone in the Mid-Atlantic and was destroyed half way around the world by a subduction zone in the Pacific? (Hint: Figure out how big half the circumference of the Earth is in cm. The radius r of the Earth is 637 million cm, or 637, 000, 000 cm or 6.37x108 cm. The full circumference is C = 2 π r where π = 3.14. Then calculate how many years would it take to travel half way around the world at 4 cm per year.)

    Bonus Question Is the rock in question 1 older than the age of crust in question 2? If so, how might this happen? (Hint: Where might the geologist have found the very old rock in question 1?)

    Thank you.