# BOB

Most popular questions and responses by BOB-
## Science

1. Which type of weather technology often carries cameras that can make images of Earth's surface, clouds, and snow cover? A. weather balloon B. weather satellite**** C. computer D. automated weather station 2. Why are weather forecasts more reliable now

*asked on March 19, 2015* -
## science

Which kind of energy transformation occurs when a skater's board falls back to the ramp?

*asked on May 13, 2016* -
## Math

A biologist has determined that a particular osprey has a 70% chance of catching a fish on any given day. Carry out a simulation of 20 trials using the random number table below to find the probability that the osprey will actually catch a fish on all of

*asked on May 20, 2014* -
## MATH MS.SUE HELP PLEASE!

Could somebody help me I don't understand any of this. Could someone show me or tell me how to work the problems? 1. Find the length of the hypotenuse of a right triangle with the legs of 9cm and 12cm A.8 B.21 C.15 D.225 2.The length of a hypotenuse of a

*asked on October 18, 2013* -
## math

Why couldn't the two elephants go swimming together?

*asked on March 17, 2009* -
## English

these lines of dialogue from the dairy of anne frank, act 1 reveal a lot about anne's character. In the paragraph , explain at least two things that you find out about anne's personality from her words. can someone start me out please im not good at essays

*asked on May 4, 2016* -
## comprehension science

how can a cyclist minimize friction as he or she rides?

*asked on May 13, 2016* -
## English

--The Watsons go to Birmingham- 1. Which of the following passages from the novel most accurately reflects the political climate of the United States in the early sixties? A. Let's see, where was the 'Coloreds only' bathroom downtown? B. Bright in the spot

*asked on January 6, 2017* -
## Algebra

Participants in a study of a new medication received either medication A or a placebo. Find P(placebo and improvement). You may find it helpful to make a tree diagram of the problem on a separate piece of paper. Of all those who participated in the study,

*asked on May 21, 2014* -
## world history

1. Which of the following would Locke most Favor? A. Republic B. Oligarchy C. Theocracy D. Absolute monarchy

*asked on January 13, 2017* -
## Math

Find the largest $n$ so that $f(2) \cdot f(3) \cdot f(4) \cdots f(n-1) \cdot f(n) < 1.98.$

*asked on February 4, 2016* -
## Chemistry

a) Which of the following reagents would oxidize Zn to Zn2 , but not Ag to Ag ? Answers are: Co2+ Ca2+ Br2- Br2 Co or Ca b) Which of the following reagents would oxidize Ag to Ag , but not Cl– to Cl2? Answers are: Co Br- Br2 Co2+ Ca2+ or Ca

*asked on June 2, 2014* -
## Chemistry

Carbon dioxide gas has a solubility of 0.0972 g/100 g H2O at 40 degrees celsius. Expressed in parts per million, this concentration is closest to... (1)0.972 ppm (2)9.72 ppm (3)97.2 ppm (4)972 ppm

*asked on February 7, 2012* -
## Calculus

for the function F(t)=ln(t^2), let f(t)=F'(t). Write the integral from a to b of f(t) dt and evaluate it with the fundamental theorem of calculus. the integral from 1 to 3 ___ dt= __

*asked on November 30, 2011* -
## chemistry

For the following: i) H3PO4 > H3AsO4 > H3SbO4 ii) H2Te > H2Se > H2S > H2O iii) HCl > HBr > HI iv) SbH3 > AsH3 > PH3 > NH3 The order of acidity is correct for which series? 1. ) all are correct 2. ) i and ii 3. )i, ii and iv 4. ) ii, iii 5. ii, iv I know

*asked on November 24, 2009* -
## Math ASAP

In a survey, one out of three people named blue as their favorite color. Two out of seven named red. If 1,092 people were included in the survey, how many named neither blue nor red as their favorite color? A. 416 people B. 432 people C. 540 people D. 512

*asked on February 9, 2017* -
## health

which is a main factor that accounts for changes in the american family structure 1.casual friends 2.close friends 3.opposite sex friends 4.personal friends

*asked on December 11, 2017* -
## Chemistry

The equilibrium constant, Kp, equals 3.40 for the isomerization reaction: cis-2-butene trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.145 atm of trans-2-butene, what is the equilibrium pressure of each gas?

*asked on December 2, 2014* -
## Pre Calculus

Find all $2 \times 2$ matrices $\bold{A}$ that have the property that for any $2 \times 2$ matrix $\bold{B}$, \[\bold{A} \bold{B} = \bold{B} \bold{A}.\]

*asked on September 20, 2017* -
## Math

2. Write a ratio for the situation in three ways comparing the first quantity to the second quantity. In union City, about one in every three homes has two cars A. 5 to 2, 5:2, 5/2 B. 1 to 3, 1:3, 1/3 C. 5 to 3, 5:3, 5/5 D. 3 to 2, 3:2, 3/2

*asked on February 7, 2017* -
## health

which is a main factor that accounts for changes in the american family structure

*asked on December 11, 2017* -
## Chemistry

Kc is 1.67 × 1020 at 25°C for the formation of iron(III) oxalate complex ion: Fe3+(aq) + 3 C2O42-(aq) [Fe(C2O4)3]3-(aq). If 0.0200 M Fe3+ is initially mixed with 1.00 M oxalate ion, what is the concentration of Fe3+ ion at equilibrium?

*asked on December 2, 2014* -
## Chemistry

How do you calculate ΔSfus and ΔSvap for HCl given melting point,ΔHfus, boiling point, and ΔHvap also how do you determine the entropy change when 5.20 mol of HCl(l) freezes at atmospheric pressure.

*asked on April 25, 2014* -
## Chemistry

40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been added, the pH in the titration flask is 5.10. What was the concentration of the original acetic acid solution? (Ka(CH3COOH) = 1.8

*asked on April 10, 2011* -
## physics

Net force F causes mass m1 to accelerate at rate a. A net force of 3F causes mass m2 to accelerate at rate 2a. What is the ratio of mass m1 to mass m2?

*asked on November 5, 2013* -
## Chemistry

In a particular redox reaction, MnO2 is oxidized to MnO4– and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in acidic solution. Phases are optional. MnO2 + Cu^2+ ---> MnO4^- + Cu^+

*asked on May 4, 2014* -
## chemistry

Calculate the pH and percentage protonation of the solute in an aqueous solution of 0.39 M quinine if the pKa of its conjugate acid is 8.52.

*asked on April 24, 2012* -
## studies

Why was inflation a problem after World War II?

*asked on May 8, 2017* -
## geometry

What is the most precise name for quadrilateral ABCD with vertices A(–3, 2), B(–1, 4), C(4, 4), and D(2, 2)? 1. parallelogram 2. rhombus 3. quadrilateral 4. rectangle

*asked on January 11, 2013* -
## physics

In a Broadway performance, an 80 kg actor swings from a 3.75 m long cable that is horizontal when he starts.? At the bottom of his arc, he picks up his 55.0 kg costar in an inelastic collision. What maximum height do they reach after their upward swing?

*asked on October 16, 2012* -
## Chemistry

Balance the following equation for a half reaction that occurs in basic solution. Use e– as the symbol for an electron. SO3^2- ---> S2O4^2-

*asked on May 4, 2014* -
## Math

Find the real part of (sqrt{3} - i)^{2011}.

*asked on August 24, 2016* -
## Math

The sum of the three smallest positive values of theta such that 4(cos*theta)(sin*theta) = 1 is k*pi. Find k. Help!!!!!

*asked on June 26, 2016* -
## english

Identify the italicized word according to its class in structural linguistics. (There) are no easy answers.

*asked on November 7, 2012* -
## Chemistry

A 150.0 mL sample of a 1.50 M solution of CuSO4 is mixed with a 150.0 mL sample of 3.00 M KOH in a coffee cup calorimeter. The temperature of both solutions and the calorimeter was 25.2°C before mixing and 31.3°C after mixing. The heat capacity of the

*asked on February 18, 2014* -
## chemisty

The molar heat capacity of C6H6(ℓ) is 136 J/mol ·◦C and of C6H6(g) is 81.6 J/mol · ◦C. The molar heat of fusion for benzene is 9.92 kJ/mol and its molar heat of vaporization is 30.8 kJ/mol. The melting point of benzene is 5.5 ◦C, its boiling

*asked on January 11, 2012* -
## science

Two stones are launched from the top of a tall building. One stone is thrown in a direction 30.0degree above the horizontal with a speed of 10.0m/s ; the other is thrown in a direction 30.0degree below the horizontal with the same speed. Which stone lands

*asked on September 8, 2008* -
## Math

Describe a real world situation that could be represented by planes slicing a three dimensional figure to form cross sections

*asked on March 5, 2017* -
## chemistry

Surface tension explains which of the follow- ing phenomena? I) A piece of aluminum foil floating on a lake II) A bowling ball sinking more slowly through molasses than through water III) Separating ethanol from water by distillation IV) Water beading on a

*asked on November 14, 2010* -
## Physics

A woman on a bridge 75.0m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 7.00m more to travel before passing under the bridge. The stone

*asked on November 19, 2013* -
## Statistics

A car manufacturer is interested in conducting a study to estimate the mean stopping distance for a new type of brakes when used in a car that is traveling at 60 miles per hour. These new brakes will be installed on cars of the same model and the stopping

*asked on November 30, 2009* -
## calculus

Coroners estimate time of death using the rule of thumb that a body cools about 2 degrees F during the first hour after death and about 1 degree F for each additional hour. Assuming an air temperature of 78 degrees F and a living body temperature of 98.6

*asked on November 18, 2010* -
## Physics

Work of 730 J is done by stirring an insulated beaker containing 80 g of water. What is the change in the temperature of the water? Please show calculation

*asked on October 19, 2011* -
## Math

ABC has vertices A(0, 6), B(4, 6), and C(1, 3). Sketch a graph of ABC and use it to find the orthocenter of ABC. Then list the steps you took to find the orthocenter, including any necessary points or slopes you had to derive.

*asked on December 7, 2012* -
## Chemistry

If Kc = 0.143 at 25°C for this reaction, find the equilibrium concentrations of C6H12 and CH3C5H9 if the initial concentrations are 0.200 M and 0.075 M, respectively. a. [C6H12] = 0.041 M, [CH3C5H9] = 0.041 M b. [C6H12] = 0.159 M, [CH3C5H9] = 0.116 M c.

*asked on January 30, 2011* -
## chemistry

Calculate the number of carbon atoms in 0.75 L of acetone (CH3COCH3). (density = 1.3 g/mL and boiling point = 48.5 degrees Celsius)

*asked on October 31, 2010* -
## Economics

A monopoly firm faces a demand curve given by the following equation: P = $500 − 10Q, where Q equals quantity sold per day. Its marginal cost curve is MC = $100 per day. Assume that the firm faces no fixed cost. You may wish to arrive at the answers

*asked on May 3, 2016* -
## science

what does a cladogram show

*asked on November 20, 2018* -
## Calculus

List x1, x2, x3, x4 where xi is the right endpoint of the four equal intervals used to estimate the area under the curve of f(x) between x = 3 and x = 5. 3, 3.5, 4, 4.5 3, 3.2, 4.6, 5 3.5, 4, 4.5, 5 3.25, 3.75, 4.25, 4.75 my answer was a because i kept

*asked on April 3, 2015* -
## Math

In first gear, or low gear, an automobile's engine runs about three times as fast as the drive shaft. In second gear, the engine does not have to run as fast; usually it runs about 1.6 times faster than the drive shaft. Finally, in third, or high gear, the

*asked on June 17, 2013* -
## main ideas

Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. A greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. The heat doesn't radiate back into the

*asked on September 6, 2013* -
## Physics

You demonstrate hitting a board in a karate class. The speed of your hand as it hits the thick board is 12 m/s with respect to the board, and the mass of your hand is about 0.74 kg. How deep does your hand go into the board before stopping if the collision

*asked on November 19, 2016* -
## chemistry

Consider the following reaction: CaCN2 + 3H2O ¨ CaCO3 + 2NH3 105.0 g CaCN2 and 78.0 g H2O are reacted. Assuming 100% efficiency, which reactant is in excess and how much is leftover? The molar mass of CaCN2 is 80.11 g/mol. The molar mass of CaCO3 is

*asked on October 31, 2010* -
## physics

A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth three times the magnitude of the

*asked on December 2, 2011* -
## math

Dents and Dings Auto Body buys paint with a list price of $29,000. If the supplier extends trade discounts of 30/35/20, what is the trade discount amount?

*asked on January 9, 2011* -
## math

Anne wants to tie a support line from the top of a 50 foot radio tower to an anchor spot 30 feet from the tower’s base. Approximately how long will the line need to be?

*asked on June 20, 2013* -
## ap calculus

a particle moves along the x axis in such a way that its acceleration at time t, t>0 , is given by x(t)= (ln x)^2. at what value of t does the velocity of the particle attain its maximum

*asked on April 5, 2013* -
## chemistry

Phosphoric acid is a triprotic acid, so H3PO4, H2PO4 -, and HPO4 2- are all acids. Which of the solutions below would have the lowest pH? 0.1 M NaH2PO4 0.1 M Na2HPO4 0.1 M Na3PO4

*asked on March 10, 2014* -
## Calculus

A wire 4 meters long is cut into two pieces. One piece is bent into a square for a frame for a stained glass ornament, while the other piece is bent into a circle for a TV antenna. To reduce storage space, where should the wire be cut to minimize the total

*asked on November 14, 2012* -
## Physics

A 1200-kg frictionless roller coaster starts from rest at a height of 24 m. What is its kinetic energy when it goes over a spot that is 12 m high?

*asked on May 10, 2012* -
## math

A 25% vinegar solution is combined with triple the amount of a 45% vinegar solution and a 5% vinegar solution resulting in 20 milliliters of a 30% vinegar solution. Write an equation that models this situation and explain what each part represents in the

*asked on November 26, 2018* -
## Us history

Which of these is an example of a monetary incentive A. Having fun walking a dog B. Making friends on a sports team C. Learning a new skill by studying it D. Earning a allowance for doing chores

*asked on June 7, 2017* -
## Math, Please Help!!!

a hot air balloon is rising vertically 10 ft/sec while the wind is blowing horizontally 5ft/sec. Find the speed of the balloon and the angle x that it makes with the horizontal. I know that the speed of the balloon is the square root of (10)^2 + (5)^2, but

*asked on November 10, 2011* -
## trig

An airplane is flying in the direction 148° with an airspeed of u = 920 kilometers per hour. Because of the wind, its groundspeed and direction are v = 820 kilometers per hour and 140°, respectively (see figure). Find the direction and speed of the wind.

*asked on November 2, 2015* -
## algebra 2

During the first part of a trip a canoeist travels 26 miles at a certain speed. The canoeist travels 8 miles on the second part of the trip at a speed 5 mph slower. Total time is 3 hours. What was the seed on each part of the trip

*asked on April 21, 2013* -
## Algebra 2

Claire has borrowed $\$5,\!000$. She plans to pay off the loan in full after two payments. She will make one payment in 3 years, then another payment in 6 years. The second payment will be exactly double the amount of the first payment. How much is the

*asked on April 4, 2017* -
## health

PLEASE HELP 1. One of your friends plays video games for at least six hours each day and gets upset when he has to eat dinner with his family. This is a sign of? a. An anxiety disorder. b. A phobia c. Bipolar disorder d. An impulse-control disorder 2. A

*asked on November 17, 2015* -
## Physics

An electron is acted upon by a force of 3.50×10−15 N due to an electric field. Find the acceleration this force produces in each case: The electron's speed is 6.00 km/s . =3.84*10^15 The electron's speed is 2.60×108 m/s and the force is parallel to the

*asked on October 30, 2017* -
## Social Studies

If I could have some help on this question I'd appreciate it.I think the answer is B. Which problem would most likely result if banks did not exist? (1 point) People would no longer be able to save money. Money would not move through the economy very well.

*asked on November 9, 2012* -
## chem

Ascorbic acid, H2C6H6O6, is a diprotic acide with a K1= 7.9 E-5 and a K2=1.6E-12. In a .005 M aq solution of ascorbic acid which of the following species is present in the lowest concentration. 1. H2O 2. H3O+ 3. H2C6H6O6 4. HC6H6O6- 5. C6H6O6-2

*asked on May 5, 2011* -
## physics

In the vertical jump, an Kobe Bryant starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat Kobe as a particle and let ymax be his maximum height above

*asked on October 21, 2010* -
## statistics

A university dean wishes to estimate the average number of hours his part-time instructors teach per week. The standard deviation is 2.6 hours. How large a sample must be selected if he wants to be 95% confident of finding whether the true mean differs

*asked on March 30, 2011* -
## physics

A 1000 kg car traveling is at 40.0 m/ s. To avoid hitting a second car the driver slams on his brakes. The brakes provide a constant friction force of 8000 N. ( a) Find the minimum distance that the brakes should be applied in order to avoid a collision

*asked on November 12, 2017* -
## Math

When Alina was hungry she ate c cookies, which was 30% of all the cookies she had. How many cookies did she have in the beginning?

*asked on April 30, 2017* -
## Physics

The diagram below shows a large cube of mass 25 kg being accelerated across a frictionless level floor by a horizontal force, F. A small cube of mass 4.0 kg is in contact with the front surface of the cube. The coefficient of static friction between the

*asked on November 15, 2012* -
## pre-algebra

a bag contains 5 green marbles 2 white marbles 8 blue marbles 9 red marbles and 6 black marbles what is the probability of drawing a white marble replacing it and then drawing a green marble? Answer choices A 1/6 B 1/15 C 1/87 D 1/90 I think its D, but I

*asked on February 17, 2011* -
## Social Studies

Identify two specific ways the Catholic Church tried to stop the spread of Protestantism

*asked on October 14, 2018* -
## math

What set of reflections and rotations would carry rectangle ABCD onto itself? Rectangle formed by ordered pairs A at negative 4, 1, B at negative 4, 2, C at negative 1, 2, D at negative 1, 1.

*asked on September 17, 2018* -
## Math

ABC has vertices A(0, 6), B(4, 6), and C(1, 3). Find the orthocenter of ABC?

*asked on November 11, 2017* -
## physics

The velocity of a particle constrained to move along the x-axis as a function of time t is given by: v(t)=-(13/t_0) sin(t/t_0). a)If the particle is at x=4 m when t = 0, what is its position at t = 5t_0. You will not need the value of t_0 to solve any part

*asked on October 21, 2010* -
## math

1. Which of the following numbers is a rational? A. 4/5 B. square root of 27 C. 4.02002000200002... D. Square root of 31 2. Which type of number is shown below? 0.313311333111... A. repeating decimal B. rational C. irrational D. terminating decimal 3.

*asked on September 21, 2016* -
## physics

a 20 kg rock is on the edge of a 100 m cliff . the rock falls from the cliff , what is its kinetic energy just before it hits the ground ?

*asked on February 6, 2012* -
## Precalculus

ool and die company buys a machine for $175,000 and it depreciates at a rate of 30% per year. (In other words, at the end of each year the depreciated value is 70% of what it was at the beginning of the year.) Find the depreciated value of the machine

*asked on February 6, 2018* -
## geometry

In the figure below, the measure of arc AC is 88 degrees if angle ABC is equal to 88 degrees.

*asked on February 19, 2012* -
## Math

AA climbing gym charges $10 to climb each day.A pair of climbing shoes costs $84.it costs $169 to buy 6 days of climbing,one pair of climbing shoes,and one harness.how much does a harness cost

*asked on November 14, 2016* -
## Chemistry

In the lab, 5.8 L of methane gas is burned with excess oxygen gas at SATP. How much carbon dioxide gas is produced? **Based on the balanced chemical equation the ratio of methane gas to carbon dioxide is 1:1, this being said, does it make sense that as 5.8

*asked on January 10, 2016* -
## Chemistry

If you were to prepare a 1.00 molal solution of CaCl2 beginning with water at 27.0 C, what would the final temperature of the solution be (in C)? Assume that the specific heats of both pure H2O and the solution are the same, 4.18 J/K*g. The dissolution of

*asked on April 18, 2011* -
## Chemistry

Calculate the total quantity of heat required to convert 25.0 g of liquid CCl4(l) from 25.0°C to gaseous CCl4 at 76.8°C (the normal boiling point for CCl4)? The specific heat of CCl4(l) is its heat of fusion is and its heat of vaporization is

*asked on April 13, 2010* -
## Trig

From a point P on level ground, the angle of elevation of the top of a tower is 27°10'. From a point 23.0 meters closer to the tower and on the same line with P and the base of the tower, the angle of elevation of the top is 51°30'. Approximate the

*asked on June 26, 2012* -
## Chemistry

Assuming all volume measurements are made at the same temperature and pressure, how many liters of carbon dioxide gas can be produced when 12.8 liters of oxygen gas react with excess carbon monoxide? Show all of the work used to solve this problem.

*asked on March 29, 2011* -
## ap chemistry

Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2CO + O2 yields 2CO2 Delta H for this reaction is -135.28 kcal. If 811.7 kcal is released, how many moles of CO must have reacted? 1). 270.5 mol 2). 40.5 mol 3). 12.0 mol

*asked on October 18, 2012* -
## Reading

What is the rhyme scheme of "Great Glorious Gobs"? A. ABAB B. BBBA C. AABB D. AABA

*asked on November 14, 2011* -
## Chemistry

This is for a lab about determining the equilibrium constant. Given: 5.00mL of .203M Fe(NO3)3 mixed with 100mL of .00205M KSCN in a .5M HNO3 solvent for both solutions. Resulting absorbance for solution is .315. How can i find the total Fe, [Fe*] and SCN,

*asked on April 3, 2011* -
## physics

A 25.1 g marble moving to the right at 22.9 cm/s overtakes and collides elastically with a 12.1 g marble moving in the same direction at 11.3 cm/s. After the collision, the 12.1 g marble moves to the right at 25.1 cm/s. Find the velocity of the 25.1 g

*asked on February 24, 2011* -
## Chemistry

Which of the following ionic compounds has the highest melting point? Help: Lattice energy Select one: a. Cs2O b. K2O c. BeO d. SrO e. LiF f. CsI

*asked on November 10, 2014* -
## Physics!!

A cart loaded with bricks has a total mass of 25.2 kg and is pulled at constant speed by a rope. The rope is inclined at 21.6 ◦ above the horizontal and the cart moves 13.7 m on a horizontal floor. The coefficient of kinetic friction between ground and

*asked on May 8, 2012* -
## algebra

What should you say if you see a tall wrought-iron tower in paris, france?

*asked on May 12, 2010* -
## physics

A piece of putty of mass m = 0.75 kg and velocity v = 2.5 m/s moves on a horizontal frictionless surface. It collides with and sticks to a rod of mass M = 2 kg and length L = 0.9 m which pivots about a fixed vertical axis at the opposite end of the rod as

*asked on November 14, 2014* -
## physics

a small bead can slide without friction on a circular hoop that is in a vertical plane and has a radius of 0.100 m. The hoop rotates at a constant rate of 3.00 rev/s about a vertical diameter. Find the angle beta at which the bead is in vertical

*asked on October 24, 2011* -
## Math

Adam used the three fractions to make a circle graph dhd

*asked on April 12, 2018*