# Bobby

Popular questions and responses by Bobby
1. ## precalculus, complex numbers

Let $\omega$ be a complex number such that $\omega^7 = 1$ and $\omega \neq 1$. Let $\alpha = \omega + \omega^2 + \omega^4$ and $\beta = \omega^3 + \omega^5 + \omega^6$. Then $\alpha$ and $\beta$ are roots of the quadratic $x^2 + px + q = 0$ for some

2. ## Physics

3. A person exerts a force of 55 N on the end of a door 74 cm wide. What is the magnitude of the torque if the force is exerted a)perpendicular to the door b)at a 45 degree angle to the door, c) at a 125 degree angle to the door?

3. ## Chemistry

The heat of combustion of benzene, C6H6, is -41.74 kJ/g. Combustion of 3.65 of benzene causes a temperature rise of 4.41 C^o in a certain bomb calorimeter. What is the heat capacity of this bomb calorimeter? (kJ/C^o) So, I what I did was I multiplied

4. ## Chemistry

The overall rate of any chemical reaction is most closely related to a) the number of steps in the reaction mechanism b)the overall reaction c) the fastest step in the reaction mechanism d)the slowest step in the reaction mechanism e) the average rate of

5. ## physics

You throw a ball toward a wall with a speed of 25m/s and at an angleof 40 degree above the horizontal. The wall is 22m from the realease point of the ball. a) How far above the release point does the ball hit the wall? b) What are the horizontal and

6. ## Chemistry

Does anyone know why Glucose is soluble in water but is not soluble in Hexane?

7. ## Physics

An aluminum bar has the desired length when at 10 degrees Celsius. How much stress is required to keep it at this length if the temperature increases to 33 degrees Celsius?

8. ## Calculus 1

A ball is thrown vertically upward from ground level with initial velocity of 96 feet per second. Assume the acceleration of the ball is a(t) = -32 ft^2 per second. (Neglect air Resistance.) (a) How long will it take the ball to raise to its maximum

9. ## Calculus

Find two numbers whose sum is 10 for which the sum of their squares is a minimum.

10. ## Math

a. Express f(x)=x^2 - 6x + 14 in the form f(x)=(x-h)^2 + k, where h and k are to be determined. b.Hence, or otherwise, write down the coordinates of the vertex of the parabola equation y=x^2 - 6x + 14.

11. ## Writing English

PLEASE HELP Does my work look correct? Underline the adverb clause in each sentence below, and then answer the questions that follow. 12. When rain falls, my socks get wet. I underlined "my socks get wet" as the adverb clause a. What word (or words) does

12. ## Math

Use a specific example to explore how the cross product behaves under scalar multiplication. Is it true that k (Vector a × Vector b) = (kVector a) × Vector b = Vector a × (kVector b)? Expand to the general case to prove your theory.

A diver stands on the end of a diving board as shown in the figure on the right. The mass of the diver is 58 kg and the mass of the uniform diving board is 35 kg. Calculate the magnitudes and directions of the forces exerted on the board at the points A

14. ## Chemistry

In a saturated solution of silver phosphate, the concentration of silver ion is 4.5 x 10^-4 mol/L. The Ksp of silver phosphate would be which of the following? 6.8  10-8 1.0  10-11 1.4  10-14 none of the above 1.5  10-15 In a saturated solution

15. ## physics

A paperweight, when weighed in air, has a weight of W = 6.8 N. When completely immersed in water, however, it has a weight of Win water = 4.3 N. Find the volume of the paperweight.

16. ## Physics

You are pulling your little sister on her sled across an icy (frictionless) surface. When you exert a constant horizontal force of 120 N, the sled has an acceleration of 1.7 m/s2 If the sled has a mass of 8.4 kg, what is the mass of your little sister?

17. ## calculus 2

Find the volume of the solid formed by rotating the region enclosed by y=e^(5x) , \ y=0, \ x=0, \ x=0.8 around the y-axis Please help, i have been attempting these problems for a couple of days

18. ## math, calculus 2

Consider the area between the graphs x+y=16 and x+4= (y^2). This area can be computed in two different ways using integrals. First of all it can be computed as a sum of two integrals integrate from a to b of f(x)dx + integrate from b to c of g(x)dx What is

19. ## Chemistry

Wh does the blue color of Iodine disapear when amylose reacts with saliva? I had thought it was because Amylase in saliva will replace the I2 in the amylose coil and thus removes the color, but I got it wrong. I know it has to be connected to the Amylase

20. ## chemistry

Assuming that 1 gram of aspirin dissolves in 450 ml of water at 10°C, how much aspirin would be lost in 40 ml of water added to the reaction mixture if the mixture were at 10 °C during filtration?

21. ## science

*Please answer quickly!* 1. Nucleic acids include RNA and DNA. The monomers of these molecules are ____. a fatty acids b amino acids c nucleotides d monosaccharides 2. Phospholipid molecules in a membrane are arranged with their ______ on the exterior and

22. ## English

Check my work? Underline the adverb clause in each sentence below, and then answer the questions that follow. 13. My grandma always yells at me because I only own two pairs of socks. I underlined " I only own two pairs of socks " as the adverb clause a.

23. ## Math

In the NFL, a division consists of 4 teams, each of which plays each other team twice. Assume that in any game, either team is equally likely to win (and there are no ties). What is the probability that, at the end of the season, the division has neither a

24. ## Chemistry

Silicon carbide, commonly known as carborundum, is a very hard and abrasive substance. The compound is prepared by heating silicon dioxide in the presence of graphitic carbon: SiO2(s) + 2C(s) --> SiC(s) + CO2(g) How many grams of silicon carbide can be

25. ## algebra

the pressure (p) that a 160-pound person's shoe exerts on the ground when walking varies inversely with area (a) of the sole of the shoe. when the shoes have a sole area of 40 sq. in., the pressure is 4 pounds per sq. in. what is the sole area of the sole

22/8 - 3/2

27. ## Language Arts

Which of the following answer choices contains a METAPHOR? a. His skin was sandpaper. b. The sun sparkled like a diamond. * c. Sh wanted to be like the birds and fly away. d. They felt free when they ran through the doors. What is a key characteristic of a

28. ## chemistry

Bromine is a red liquid at 25°C. Its density is 3.12 g/mL. What is the volume of 28.1 g of liquid bromine?

75. ## Physics

A ball is thrown horizontally from the building roof at a speed of 20 m/s. Takes ball 4 seconds to reach the ground. How tall is building? What is the ball’s speed and direction as it contacts the ground? How far from the base of the building does the

76. ## Math

What is the range between 58 degrees and -88 degrees

77. ## English

What roles are played by the female characters you encountered in this unit? Describe some of these female characters, their traits, and the roles they played within the selections you read, especially considering that all of those selections had male

78. ## physics

Mayan kings and many school sports teams are named for the puma, cougar, or mountain lion Felis concolor, the best jumper among animals. It can jump to a height of 12.2 ft when leaving the ground at an angle of 44.2°. With what speed, in SI units, does it

79. ## Algebra 2

A right triangle has a 45 degree angle. The hypotenuse is x and the leg is 8. Find the value of x.

80. ## Algebra

Tell whether the lines for each pair of equations are parallel perpendicular or neither. Y= -2x + 4 -5+10y=5 I think perpendicular Next question is same kind- Y=-1/4x+10 -2x+8y=6 I think it's neither

81. ## Algebra

Flying against the wind, an airplane travels 28 km in 5 hours. Traveling with the win, the same plane travels 3760km in 4 hours. What is the rate of the plane and still air and what is the rate of the wind?

82. ## Logarithms

Solve the following equations for x and check the solution using log. 2^6x-1 = 28 The answer is log56/6log2. Explain each step.

83. ## chemistry

3A+2B+2C > 4D+2E 1) what is the rate of this reaction in terms of change of concentration of reactant B? - is it '1/2' ? 2) what is the rate of this reaction in terms of change of concentration of product D? please help

84. ## statistics

the standard score for hours spent online at home for Minnesotans was 2.84. The mean equals 8.9 hours. Approximately how many hours do Minnesotan adults spend online at home.

85. ## Science

When magnesium oxide (MgO) and water (H20)react, they produce magnesium hydroxide Mg(OH)2. Magnesium hydroxide is a medicine used to treat an upset stomach. The equation for this chemical change is shown below: MgO + H20 --> Mg(OH)2 if 40.00 grams of

86. ## statistics

1)According to past record the average daily sales for a sporting goods store was \$3456.00. After a new advertising campaign, the manager wants to see if the average daily sales have changed. A random sample of 20 days gives a sample mean of 3655 with a

87. ## Physics

The atomic mass of a nitrogen atom (N) is 14.0 u, while that of an oxygen atom (O) is 16.0 u. Three diatomic gases have the same temperature: nitrogen (N2), oxygen (O2), and nitric oxide (NO). Rank these gases in ascending order (smallest first), according

88. ## Physics

The cylinder in the drawing contains 3.81 mol of an ideal gas. By moving the piston, the volume of the gas is reduced to one-fourth its initial value, while the temperature is held constant. How many moles Δn of the gas must be allowed to escape through

89. ## statistics

If a milk cow in California produced a mean of 1,875 pounds of milk per month, what percentage of production would that cow be in compared to the overall production per milk cow in California from 1990 through 2005?

A ladder, 5.0 m long, leans against a frictionless wall at a point 4.0 m above the ground. A painter is climbing up the ladder. The mass of the ladder is 12.0 kg and the mass of the painter is 60.0 kg. The ladder begins to slip at its base when the painter

91. ## economics

The demand curve for knobs is P=75-6QD and the supply curve for knobs is P=35+2QS. What is the equilibrium price of a knob?

92. ## math

show that the equation x^3-15x+c=0 has at most one root on the interval [-2,2.

93. ## biology

An individual with the genetic condition cystic fibrosis has CFTR protein with the amino acid histidine (at position 482), where the normal CFTR protein has arginine. (No other changes are observed in the protein.) This is the result of a _________

94. ## biology

Which of the following is NOT true of transcription / translation processes in both bacteria and eukaryotes? Select one: a. RNA polymerase reads the template DNA strand to produce the complementary mRNA transcript. b. Translation of a polypeptide can occur

95. ## chemistry

how do u hybridize for sulfate (SO4 -2)?

96. ## phyics

A person who weighs 829 N steps onto a spring scale in the bathroom, and the spring compresses by 0.538 cm. (a) What is the spring constant? (b) What is the weight of another person who compresses the spring by 0.390 cm?

97. ## phyics

You are installing a new spark plug in your car, and the manual specifies that it be tightened to a torque that has a magnitude of 65 N·m. Using the data in the figure, determine the magnitude F of the force that you must exert on the wrench.

98. ## Chemistry

The protective action of ozone in the atmosphere comes through ozone's absorption of UV radiation in the 230 to 290 nm wavelength range. What is the energy, in kilojoules per mole, associated with radiation in the wavelength range?