Helga

Newest questions posted by Helga
  1. Physics

    A jetliner flies west 2,000 miles from Chicago you San Francisco. It has an average speed of 635 mph relative to the air. What is the velocity of the jetliner relative to the earth of the wind is blowing at 160 mph from the west to the east? 475 mph, east
  2. Physics

    Please help!!! A jetliner flies west 2,000 miles from Chicago you San Francisco. It has an average speed of 635 mph relative to the air. What is the velocity of the jetliner relative to the earth of the wind is blowing at 160 mph from the west to the east?
  3. Physics

    A jetliner flies west 2,000 miles from Chicago you San Francisco. It has an average speed of 635 mph relative to the air. What is the velocity of the jetliner relative to the earth of the wind is blowing at 160 mph from the west to the east? 475 mph, east
  4. Physics

    A jetliner flies west 2,000 miles from Chicago you San Francisco. It has an average speed of 635 mph relative to the air. What is the velocity of the jetliner relative to the earth of the wind is blowing at 160 mph from the west to the east? 475 mph, east
  5. Physics

    4. In a shopping mall, two elevators pass each other moving in opposite directions. Each elevator to the other is 10 m/s. What is the velocity of each elevator relative to a person standing on the ground? One elevator has a velocity of 5 m/s and the other
  6. Physics

    A Dodge Stealth is driving at 70 mph on a highway. It passes a BMW going the same direction. The BMW is moving 7 mph backward relative the Dodge. What is the velocity of the BMW? Let the positive direction be forward. -63 mph -77 mph 77 mph 63 mph A
  7. Physics

    A helicopter above the ground is descending at 3.5 m/s. It drops a package from rest(relative to the helicopter). Just before it hits the ground the package is falling at a rate of 13.4 m/s relative to the ground. Find the velocity of the package relative
  8. history

    Which laws called for strict separation of the races in the South? (1 point) anti-discrimination laws Plessy v. Ferguson laws Jim Crow laws ***** boycott laws 2. Civil rights activists targeted segregation in interstate transportation (1 point) because
  9. maths

    The cost of a gift is shared amongst 3 kids. Keith paid €480 more than jack. Keith paid €220 more than the total amount paid by Jack and tim. Jack paid 80 more than tim. How much did the present cost?
  10. Chemistry

    One of the reactions that occurs in a blast furnace, in which iron ore is converted to cast iron, is Fe2O3 + 3CO → 2Fe + 3CO2 Suppose that 1.59 × 103 kg of Fe is obtained from a 2.54 × 103 kg sample of Fe2O3. Assuming that the reaction goes to
  11. Math

    8 people are going to sit on 6 chairs. Two of them John and Kelly can't sit next to each other. How many ways can you put the people to seats? The answer is 10080, but I can't figure out how to calculate it.
  12. calculus

    Consider the function f(x)=x^n for positive integer values of n. (a) For what values of n does the function have a relative minimum at the origin? (b) For what values of n does the function have a point of inflection at the origin?
  13. Chemistry

    In the titration of 20.00 mL of 0.175 M NaOH, calculate the number of milliliters of 0.200 M HCl that must be added to reach a pH of 12,55. I know the answer is 11,9 mL but I don't know how to calculate it.
  14. research

    A quantitative analysis method which aggregates a number of (similar) individual studies into a large data set from which to compute an over all “effect size” (based on similar study procedures and treatments) is commonly known as…?
  15. Chemistry

    when 20 ml of a .10 M silver nitrate solution is mixed with 25 ml of a 0.080 M solution of sodium sulfide, producing a precipitate of silver sulfide, what is the final concentration of sulfide ion?
  16. Chemistry

    The oxides of Group 2A metals (symbolized by M here) react with carbon dioxide according to the following reaction: MO(s) + CO2(g)  MCO3(s) A 2.85-g sample containing only MgO and CuO is placed in a 3.00-L container. The container is filled with CO2
  17. Chemistry

    A bicycle tire is filled with air to a pressure of 610 kPa at a temperature of 19 oC. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58 oC. The volume of the tire increases by 4.0%. What is the new pressure in the bicycle
  18. Algebra

    How do I calculate 4^n=1/(2(n-n^2))? Thanks.
  19. Binomial expansion

    The coefficient of x^2 in the expansion of (4-3x)^n as a series of ascending powers of x is -9/64. Show that n satisfies the equation 4^(n+1)=2/[n(1-n)] and hence verify that n=1/2. I can do the first part of the problem: 4^n*3^2*n(n-1)/2!*2^4=-3^2/2^6
  20. Newton's Law of Cooling

    You are a forensic doctor called to a murder scene. When the victim was discovered, the body temperature was measured and found to be 20°C. You arrive one hour later and find the body temperature at that time to be 18°C. Assuming that the ambient
  21. Calculus

    A container in the form of a right circular cone of height 16 cm and base radius 4 cm is held vertex downward and filled with liquid. If the liquid leaks out from the vertex at a rate of 4 cm^3/s, find the rate of change of the depth of the liquid in the
  22. Calculus

    A right circular cone has a constant volume. The height h and the base radius r can both vary. Find the rate at which h is changing with respect to r at the instant when r and h are equal.
  23. Pre-Calculus

    It may look lame but I can't work out how to solve (-9) sqrt(4-x^2) = 4x + 5sqrt2. I need some guidance, please.
  24. Calculus

    Differentiate x^2*y^2 = (y+1)/(x+1) in terms of x and y. PS My answer is unfortunately at odds with that provided by the authors of the book (i.e. -y (y+1) (3x+2) all over x (x+1) (y+2), and I don't know whether it's a misprint or my method is wrong.
  25. Calculus

    If f(x) = x ln(1+x) estimate the value of ln (2.1) given that ln2 = 0.6931.
  26. Westen Civ.

    Which governmental bodies are responsible for making laws in the United States? How does a written law protect American democracy?
  27. History on WW1

    How did President Wilson use Russia's democratic revolution to gain support for the war?
  28. stat math

    Stat hw question help me please? In a high profile murder case a sample of the general public's opinions concerning the guilt or innocence of the defendant is taken. A sample of n=100 males results in 62% of the respondents beliving that the defendant is
  29. math

    A random sample of the houses in a particular city is selected and each of the houses in a particular city is selected and each of the house's level of radon gas is measured. The values collected are given in the table below in parts per million (ppm). 4 8
  30. statistics

    what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25 and 5 d. 5 and 1.25 e. 25