Friday
July 25, 2014

Posts by katie


Total # Posts: 1,679

physics
An automobile tire has a radius of 0.455 m, and its center moves forward with a linear speed of v = 15.7 m/s. Determine the angular speed of the wheel.

physics
Starting from rest at t = 0 s, a wheel undergoes a constant angular acceleration. When t = 1.6 s, the angular velocity of the wheel is 5.5 rad/s. The acceleration continues until t = 17 s, when the acceleration abruptly changes to 0 rad/s2. Through what angle does the wheel ro...

math
"joyce is decorating her store window for a going-out-of-business sale. she wants to design some art that looks like the diagram shown below. She will paint the shaded portion. How many square meters will she need to paint?"

Trig
Prove sin(α+β)sin(α-β)=cos^2β-cos^2α

Trig
A ship leaves port with a bearing of S 40 W. After traveling 7 miles, the ship turns 90 degrees on a bearing of N 50 W for 11 miles. At that time, what is the bearing of the ship from port?

Trig
Prove cos^2t+4cost+4/cost+2=2sect+1/sect

Trig
Prove (3cosθ-4sinθ)^2+(4cosθ+3sinθ)^2=25

Trig
Prove sin(α+β)sin(α-β)=cos^2β-cos^2α

Trig
A ship leaves port with a bearing of S 40 W. After traveling 7 miles, the ship turns 90 degrees on a bearing of N 50 W for 11 miles. At that time, what is the bearing of the ship from port?

Trig
Prove cos^2t+4cost+4/cost+2=2sect+1/sect

trig
Q1: Prove cos^2t+4cost+4/cost+2=2sect+1/sect Q2: A ship leaves port with a bearing of S 40 W. After traveling 7 miles, the ship turns 90 degrees on a bearing of N 50 W for 11 miles. At that time, what is the bearing of the ship from port?

Trig
prove sin(α+β)sin(α-β)=cos^2β-cos^2α please help... this is the only one I didn't understand out of all my homework...

English
I'm looking for a short summary of The Great Gatsby that is just a few sentences, but I can only find long ones!

physics
Starting from rest at t = 0 s, a wheel undergoes a constant angular acceleration. When t = 1.6 s, the angular velocity of the wheel is 5.5 rad/s. The acceleration continues until t = 17 s, when the acceleration abruptly changes to 0 rad/s2. Through what angle does the wheel ro...

Englishb
What are some books that could instruct someone on the world we live in?

English
In the book Frankenstein, the monster reads three books that he found in the forest. He learned about life from these books. My assignment is to come up with my one three books and explain why these would be important and what kind of lessons the monster would learn in order t...

8th grade math
1) subtract y from both sides 2) add 2 to both sides, subtract 1/4x from both sides 3)subtract 3 from both sides, subtract 6x from both sides hope that helps

chemistry
i got the same mm

Trig
(cos^2t+4cos^2+4)/(cost+2)=(2sect+1)/sect

Trig
Prove (cos^2t+4cos^2+4)/(cost+2)=2sect+1)/sect

Trig
prove(sinx/cosx+1)+(cosx-1/sinx)=0 Please help asap!!!!! PLEASE

Trig
prove(sinx/cosx+1)+(cosx-1/sinx)=0

physics
thank you!

physics
Wheel A of radius ra = 14.6 cm is coupled by belt B to wheel C of radius rc = 30.2 cm. Wheel A increases its angular speed from rest at time t = 0 s at a uniform rate of 5.0 rad/s2. At what time will wheel C reach a rotational speed of 52.9 rev/min, assuming the belt does not ...

physics
In a game of pool, the cue ball strikes another ball initially at rest. After the collision, the cue ball moves at 4.15 m/s along a line making an angle of -25° (i.e. below the x-axis) with its original direction of motion (the x-axis), and the second ball has a speed of 2...

physics
I don't quite follow

physics
A 500-kg cannon and a supply of 80 cannon balls, each with a mass of 45.0 kg, are inside a sealed railroad car with a mass of 11000 kg and a length of 49 m. The cannon fires to the right; the car recoils to the left. The cannon balls remain in the car after hitting the wall. A...

physics
Two identical steel balls, each of mass 5.0 kg, are suspended from strings of length 29 cm so that they touch when in their equilibrium position. We pull one of the balls back until its string makes an angle θ = 25° with the vertical and let it go. It collides elastic...

physics
Determine for each of the following statements whether it is always true or can be false. In a perfectly inelastic collision, the kinetic energy is conserved. Kinetic energy is conserved in an elastic collision. Two objects of different masses but moving at the same velocity h...

chemistry
Calculate the standard reduction potential for the reaction of Cu(III) to Cu(II) Use the following data: 1) Cu^+3 + 2e^- -> Cu^+, E°1 = 1.28 V 2) Cu^+2 + e^- -> Cu^+, E°2 = 0.15 V 3) Cu^+2 + 2e^- -> Cu(s), E°3 = 0.34 V 4) Cu^+ + e^- -> Cu(s), E°4 = ...

chemistry
Current is applied to an aqueous solution of lithium sulfide. What is the cathode and what is the anode?

chemistry
Calculate the cell potential for the following reaction as written at 53 °C, given that [Zn2 ] = 0.862 M and [Ni2 ] = 0.0110 M. Standard reduction and oxidation potentials can be found here. Zn(s) + Ni^2+(aq) --> Zn^2+(aq) + Ni(s)

chemistry
I've done this problem 4 times and keep getting it wrong. Could you please check my work? 3e- + Au^3+ --> Au and E=1.52 Ni--> Ni^2+ + 2e- and E = .26 total E = 1.78 dGo = -12(9.65x10^4)(1.78) = -2061240J or -2061.24kJ

chemistry
for n do you have to use the balanced number of before balancing? i would assume balance it first but i wanted to double check

chemistry
Calculate the standard free-energy change for the following reaction at 25 °C. 2Au^3+(aq) + 3Ni(s) -->2Au(s) + 3Ni^2+(aq)

chemistry
The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2 (aq, 0.100 M)||Zn2 (aq, ? M)|Zn(s) is 23.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode.

chemistry
Rank these species by their ability to act as an oxidizing agent. Na^+ I2 Cr^3+ F2 Put best oxidizing agent first and continue to have best reducing agent last.

physics
The drawing below shows two laboratory carts (each has a mass of 1.0 kg) X and Y in contact with a compressed exploder spring between them. The mass on cart Y is 2.33 kg, distance A is 6 cm, distance B is 9 cm. What mass must be placed on cart X, such that after the explosion ...

Math
Use this equation to estimate typing speed, S=w/5-2e, where S is the accurate typing speed, w is the number of words typed in 5 minutes, and e is the number of errors. Choose the letter for the best answer. One of the qualifications for a job is a typing speed of at least 65 w...

Science
Na subscript 2SO subscript 4 + CaCl subscript 2 produces CaSO subscript 4 + NaCl Please help me balance this equation and show your work

MATH
find the equation of the line tangent to f(x)=2x^3-x^2+1 at x=2. write in point slope form

chemistry
A galvanic cell consists of an electrode composed of nickel in a 1.0 M nickel(II) ion solution and another electrode composed of silver in a 1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction a...

chemistry
A galvanic cell consists of an electrode composed of nickel in a 1.0 M nickel(II) ion solution and another electrode composed of silver in a 1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction a...

Chemistry
Write the equations describing the electrode reactions and the net cell reaction for this electrochemical cell containing tin and silver: Sn(s)|Sn2 (aq)||Ag (aq)|Ag(s) what is the equation for cathode, anode, and net cell reaction

Chemistry
Write the equations describing the electrode reactions and the net cell reaction for this electrochemical cell containing tin and silver: Sn(s)|Sn2 (aq)||Ag (aq)|Ag(s) what is the equation for cathode, anode, and net cell reaction

physics
Thanks. the impulse is correct but the magnitude of the average force is not.

physics
A 220-g ball strikes a wall with a speed of 7.0 m/s and rebounds with only 37% of its kinetic energy. What is the speed of the ball immediately after rebounding? What is the magnitude of the impulse of the ball on the wall? If the ball was in contact with the wall for 9.9 ms, ...

physics
a) A set of crash tests consists of running a test car moving at a speed of 12.6 m/s (27.7 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 69.0 kg (151.8 lbs) dummy is found to move a distance of 0.600 m from the moment the car touches the wall to ...

chemistry
The quantity of antimony in an ore can be determined by an oxidation-reduction titration with an oxidizing agent. The ore is dissolved in hot, concentrated acid and passed over a reducing agent so that all the antimony is in the form Sb3 (aq). The Sb3 (aq) is completely oxidiz...

English
Does Victor have an obligation to the monster? Use evidence from Chapters 9-14 of Volume 2.

physics
P is to the left

english
Does Victor have an obligation to the monster in Frankenstein? Why?

MATH
√5sec²x-2secx=5 i have to solve this equation on the interval [0, 2π).

physics
The string in the Figure is L = 135.0 cm long and the distance d to the fixed peg P is 94.5 cm. When the ball is released from rest in the position shown, it will swing along the dashed arc. How fast will it be going when it reaches the lowest point in its swing? How fast will...

physics
A 0.40-kg block slides along a small track with elevated ends and a flat central part. The flat part has a length L = 1.84 m. The curved portions of the track are frictionless, but for the flat part the coefficient of kinetic friction is 0.132. The block is released from rest ...

physics
A stone with mass m = 2.3 kg is thrown vertically upward into the air with an initial kinetic energy of 190 J. The drag force acting on the stone throughout its flight is constant, independent of the velocity of the stone, and has a magnitude of 2.3 N. What is the maximum heig...

Chemistry
Calucluate the pH of 100 mL of buffer that is 0.075 M NH4Cl and 0.175 M NH3 before and after the addition of 1.00 mL of 5.05 M HNO3 I have no idea where to even start. HELP!

Chemistry
Calucluate the pH of 100 mL of buffer that is 0.075 M NH4Cl and 0.175 M NH3 before and after the addition of 1.00 mL of 5.05 M HNO3 I have no idea where to even start. HELP!

physics
With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?

physics
A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

physics
thank you

physics
A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

chemistry
At 25 °C, the equilibrium partial pressures for the following reaction were found to be PA = 6.30 atm, PB = 7.20 atm, PC = 6.40 atm, and PD = 9.10 atm. 2A(g) + 2B(g)-->C(g) + 3D(g) What is the standard change in Gibbs free energy of this reaction at 25 °C.

physics
With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?

physics
A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

Chemistry
A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...

chemistry
A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...

chemistry
Write the balanced chemical equation for each of these reactions. Include phases. However, when additional aqueous hydroxide is added the precipitate redissolves forming a soluble [Pb(OH)4]2–(aq) complex ion.

chemistry
Which of the following will be more soluble in an acidic solution than in pure water? AgBr Be(OH)2 RbClO4 CaCO3 PbSO4

chemistry
Silver chromate is sparingly soluble in aqueous solutions. The Ksp of Ag2CrO4 is 1.12× 10–12. What is the solubility (in mol/L) of silver chromate in 1.00 M potassium chromate aqueous solution?

chemistry
At a certain temperature, the solubility of strontium arsenate, Sr3(AsO4)2, is 0.0510 g/L. What is the Ksp of this salt at this temperature?

chemistry
At 25 °C only 0.0580 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?

chemistry
A generic salt, AB2, has a molar mass of 159 g/mol and a solubility of 3.30 g/L at 25 °C. What is the Ksp of this salt at 25 °C?

chemistry
Write the balanced chemical equation for each of these reactions. Include phases. When aqueous sodium hydroxide is added to a solution containing lead(II) nitrate, a solid precipitate forms. However, when additional aqueous hydroxide is added the precipitate redissolves formin...

chemistry
Copper(I) ions in aqueous solution react with NH3(aq) according to Cu+(aq) + 2NH3(aq) -->Cu(NH3)2^+ Kf = 6.3x10^10 Calculate the solubility (in g·L–1) of CuBr(s) (Ksp = 6.3× 10–9) in 0.41 M NH3(aq).

chemistry
thank you

chemistry
I posted a few questions and they all disappeared so i reposted.

chemistry
I posted a few questions and they all disappeared so i reposted.

chemistry
At 25 °C only 0.0990 mol of the generic salt AB is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?

Chemistry
What additional information would be needed to calculate the rate in units of concentration per time?

math
multiply 6sqrt25x^3*sqrt4x^3

algebra
multiply 6sqrt25x^3

physics
Two blocks with masses m1 = 20.7 kg and m2 = 55.5 kg, shown in the figure, are free to move. The coefficent of static friction between the blocks is 0.74 but the surface beneath m2 is frictionless. What is the minimum force F required to hold m1 against m2?

Chemistry
20.7mL of ethanol (density=0.789g/mL) initially at 8.2 degrees Celsius is mixed with 37.1 mL of water (density=1.0g/mL) initially at 25.7 degrees Celsius in an insulated beaker. Assuming that no heat is lost, what is the final temperature of the mixture? This is how I set up t...

chemistry
Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

chemistry
A cook wants to heat 1.10kg of water from 33 C to 100 C. If he uses the combustion of natural gas which is exothermic to heat the water, how much natural gas will he need to burn? Natural gas produces 49.3 kJ/gram.

chemistry
Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

Physics
A car that weighs 14600.0 N is initially moving at a speed of 58.0 km/hr when the brakes are applied and the car is brought to a stop in 4.7 s. Find the magnitude of the force that stops the car, assuming it is constant.

math
While riding your motorcycle, you break to miss hitting a dog. your tires leave a skid mark as you come to a stop. the skid mark forms four angles when it crosses the painted line on the side of the road. one angle formed a 62 degree angle. what other angles are formed?

chemistry
At 20 °C, chloroform (CHCl3) has a density of 1.489 g/mL. What is the mass of 7.52 mL of chloroform at 20°C?

chemistry
When 15.5 + 0.125 + 2.55 are added, the answer with the correct number of significant figures is

ANATOMY
the three major vessels of the portal triad are the hepatic artery, hepatic portal vein and bile duct. What is the location of the triad relative to the liver lobules?

science
Circle the term that does not belong in each of the following groupings. 1. HC1 secretion Acetyicholine Histamine Secretin Gastrin 2. Gastric emptying Slowed by fats Enterogastric reflex Solid foods 3. Cephalic phase Reflex phase Intestinal phase Psychological stimuli 4. Saliv...

Physics
A ball is thrown horizontally from the roof of a building 29.7 m high at 39.6 m/s. (a) What is the vertical velocity of the ball when it lands? (use down as the positive y-axis direction)b) What is the ball’s total velocity (speed and direction) when it lands?

physics
The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (as shown in the figure below). Suppose that you loft the ball with an initial speed of v = 15.6 m/s, at an...

chemistry
What is the pH of a 2.8 M solution of HClO4?

chemistry
What is the pH of a 2.8 M solution of HClO4?

chemistry
i didnt know ph could be greater than 14 and poh less than 0

chemistry
A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.

chemistry
A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.

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