Tuesday

May 3, 2016
Total # Posts: 1,913

**6th grade math**

35/(2+5)(2^3)-15
*March 28, 2012*

**physics**

A mass of 0.7 kg is attached to the end of a massless spring of spring constant 0.35 N/m. It is released from rest from an extended position. After 0.8 s, the speed of the mass is measured to be 1.5 m/s. What is the amplitude of oscillation? What is the total energy (relative ...
*March 28, 2012*

**physics**

A 390.0 g block is dropped onto a vertical spring with a spring constant k = 252.0 N/m. The block becomes attached to the spring, and the spring compresses 0.15 m before momentarily stopping. While the spring is being compressed, what work is done by the block's weight? ...
*March 28, 2012*

**physics**

A cylinder of mass M=58 kg, radius R=1.3 m and moment of inertia I=(1/2)MR2 is initially rotating around its central axis with an angular velocity ωi= 1.8 rad/s. A tangential force F of constant magnitude applied to the edge of the cylinder during 5.9 s brings it to rest...
*March 25, 2012*

**physics**

A bug that has a mass mb = 1 g walks from the center to the edge of a disk that is freely turning at 38 rpm. The disk has a mass of md = 11 g. If the radius of the disk is R = 30 cm, what is the new rate of spinning in rpm?
*March 25, 2012*

**chemistry**

using the following mechanism, determine the rate law. 2A <-- --> B+C B+D --> E 2A + D --> C + E k=? please indicate which k you are using for which equation
*March 25, 2012*

**chemistry**

The following reaction is a single-step, bimolecular reaction: CH3Br + NaOH --> CH3OH + NaBr When the concentrations of CH3Br and NaOH are both 0.135 M, the rate of the reaction is 0.0070 M/s. (a) What is the rate of the reaction if the concentration of CH3Br is doubled? (b...
*March 24, 2012*

**chemistry**

A particular reactant decomposes with a half-life of 103 s when its initial concentration is 0.397 M. The same reactant decomposes with a half-life of 213 s when its initial concentration is 0.192 M. what is the reaction order and rate constant
*March 24, 2012*

**chemistry**

A particular reactant decomposes with a half-life of 103 s when its initial concentration is 0.397 M. The same reactant decomposes with a half-life of 213 s when its initial concentration is 0.192 M. Determine rate order and rate constant.
*March 24, 2012*

**chemistry**

The rate constant for this first-order reaction is 0.320 s–1 at 400 °C. A--> Products How long (in seconds) would it take for the concentration of A to decrease from 0.830 M to 0.220 M?
*March 23, 2012*

**chemistry**

The reaction described by this equation O3(g) + NO(g) -- O2(g) + NO2(g) has the following rate law at 310 K. rate of reaction = 3.0x10^6 M^-1 s^-1)[O3][NO] Given that [O3]=2.0× 10–4 M and [NO]=2.0× 10–5 M at t=0, calculate the rate of the reaction at t=0.
*March 23, 2012*

**physics**

A vibration platform oscillates up and down with an amplitude of 8.8 cm at a controlled variable frequency. Suppose a small rock of unknown mass is placed on the platform. At what frequency will the rock just begin to leave the surface so that it starts to clatter?
*March 23, 2012*

**chemistry**

I really don't understand rate law. Could you explain that and help with this problem please? Determine the average rate of change of B from t=0 s to t=202 s. A-->2B Time (s) Concentration of A (M) 0 0.74 101 0.45 202 0.16
*March 23, 2012*

**physics**

Thank you!
*March 23, 2012*

**physics**

A 55.0 kg circus performer oscillates up and down at the end of a long elastic rope at a rate of once every 7.20 s. The elastic rope obeys Hooke's Law. By how much is the rope extended beyond its unloaded length when the performer hangs at rest?
*March 23, 2012*

**physics**

A spherically symmetric object, with radius R = 0.50 m and mass M = 1.3 kg, rolls without slipping across a horizontal floor, with velocity V = 2.1 m/s. It then rolls up an incline with an angle of inclination θ = 25° and comes to rest a distance d = 3.0 m up the ...
*March 21, 2012*

**Geometry ONE MULTIPLE CHOICE QUESTION PLEASE HELP!**

Thank you! Yes that helps! :D
*March 20, 2012*

**Geometry ONE MULTIPLE CHOICE QUESTION PLEASE HELP!**

The vertices of a triangle are P(–4, 1), Q(–2, –8), and R(8, –1). Name the vertices of the image reflected across the x-axis. P'(–4, –1), Q'(–2, 8), R' (8, 1) P'(4, –1), Q'(2, 8), R'(–8, 1) P'(4, 1), Q&#...
*March 20, 2012*

**math**

integreal 3cot^2 4xdx
*March 19, 2012*

**physics**

Two children, each with mass m = 11.0 kg, sit on opposite ends of a narrow board with length L = 4.5 m, width W = 0.30 m, and mass M = 9.4 kg. The board is pivoted at its center and is free to rotate in a horizontal circle without friction. What is the rotational inertia of ...
*March 16, 2012*

**physics**

Three particles, each of mass 3.0 kg, are fastened to each other and to a rotation axis by three massless strings, each 0.360 m long, as shown in the Figure. The combination rotates around the rotation axis with an angular velocity of 19.0 rad/s in such a way that the ...
*March 16, 2012*

**physics**

The following objects are released from rest and allowed to roll down an inclined plane. Rank the objects by the order of which they will arrive at the bottom of the incline. (1 = the first to arrive, 2 = the second, etc.) I = 2611 kg*m^2, M = 50 kg, R = 0.8 m I = 2883 kg*m^2...
*March 16, 2012*

**physics**

A ball of radius 0.211 m rolls along a horizontal table top with a constant linear speed of 3.41 m/s. The ball rolls off the edge and falls a vertical distance of 2.27 m before hitting the floor. What is the angular displacement of the ball while the ball is in the air?
*March 16, 2012*

**physics**

A train is rounding a circular curve whose radius is 1.87E+2 m. At one instant, the train has an angular acceleration of 1.51E-3 rad/s2 and an angular speed of 0.0470 rad/s. Find the magnitude of the total acceleration (centripetal plus tangential) of the train.
*March 16, 2012*

**physics**

A race car, starting from rest, travels around a circular turn of radius 20.8 m. At a certain instant, the car is still accelerating, and its angular speed is 0.515 rad/s. At this time, the total acceleration (centripetal plus tangential) makes an angle of 35.1° with ...
*March 16, 2012*

**physics**

A lunch tray is being held in one hand, as the figure below illustrates. The mass of the tray itself is 0.182 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.08 kg plate of food and a 0.279 kg cup of coffee. Assume L1 = 0.0590 m, L2 = 0....
*March 16, 2012*

**english**

what's a semiotic analysis? I've never heard of it and my teacher won't explain it. He says we have to use quotes from 2 articles also but when I put them in he yells and says to develop my own ideas. I don't get it.
*March 16, 2012*

**english**

The subject of this unit is the role of those mythologies which determine the meaning of being male or female in American culture. As always, your aim as a writer is to incorporate what the critics have been arguing into your own thinking, thereby to enter into a discussion ...
*March 16, 2012*

**Chemistry **

What is the value of Kf for the formation of the ammine M(NH3)2+ ? Assume the concentration of M(NH3)n+ = 0.0020 M The data were graphed giving a straight line plot with an equation of y = -5.9484x - 9.74. .
*March 15, 2012*

**physics**

A solid rod of mass M = 1.00 kg and length L = 85 cm is suspended by two strings, each with a length d = 83 cm (see Figure), one at each end of the rod. The string on side B is cut. What is the magnitude of the initial tangential acceleration of end B? The string on side B is ...
*March 13, 2012*

**physics**

The mass of the tray itself is 0.182 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.08 kg plate of food and a 0.279 kg cup of coffee. Assume L1 = 0.0590 m, L2 = 0.138 m, L3 = 0.258 m, L4 = 0.381 m and L5 = 0.401 m. Obtain the force T ...
*March 13, 2012*

**math**

15/23 in lowest terms yes or no
*March 12, 2012*

**physics**

A small block of mass m = 1.1 kg slides, without friction, along the loop-the-loop track shown. The block starts from the point P a distance h = 56.0 m above the bottom of the loop of radius R = 17.0 m. What is the kinetic energy of the mass at the point A on the loop? What is...
*March 11, 2012*

**physics**

A small block of mass m = 1.1 kg slides, without friction, along the loop-the-loop track shown. The block starts from the point P a distance h = 56.0 m above the bottom of the loop of radius R = 17.0 m. What is the kinetic energy of the mass at the point A on the loop? What is...
*March 11, 2012*

**physics**

The rope of a swing is 3.2 m long. Calculate the angle from the vertical at which a 95-kg man must begin to swing in order to have the same kinetic energy at the bottom as a 1500-kg car moving at 1.07 m/s (2.39 mi/hr).
*March 11, 2012*

**physics**

A constant force of 40.7 N, directed at 29.9° from horizontal, pulls a mass of 13.7 kg horizontally a distance of 2.93 m. Calculate the work done by the force.
*March 11, 2012*

**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.
*March 11, 2012*

**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 ...
*March 11, 2012*

**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?"
*March 8, 2012*

**Trig**

Prove sin(α+β)sin(α-β)=cos^2β-cos^2α
*March 5, 2012*

**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?
*March 5, 2012*

**Trig**

Prove cos^2t+4cost+4/cost+2=2sect+1/sect
*March 5, 2012*

**Trig**

Prove (3cosθ-4sinθ)^2+(4cosθ+3sinθ)^2=25
*March 5, 2012*

**Trig**

Prove sin(α+β)sin(α-β)=cos^2β-cos^2α
*March 5, 2012*

**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?
*March 5, 2012*

**Trig**

Prove cos^2t+4cost+4/cost+2=2sect+1/sect
*March 5, 2012*

**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?
*March 5, 2012*

**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...
*March 5, 2012*

**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!
*March 5, 2012*

**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 ...
*March 5, 2012*

**Englishb**

What are some books that could instruct someone on the world we live in?
*March 5, 2012*

**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 ...
*March 5, 2012*

**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
*March 4, 2012*

**chemistry**

i got the same mm
*March 4, 2012*

**Trig**

(cos^2t+4cos^2+4)/(cost+2)=(2sect+1)/sect
*March 3, 2012*

**Trig**

Prove (cos^2t+4cos^2+4)/(cost+2)=2sect+1)/sect
*March 3, 2012*

**Trig**

prove(sinx/cosx+1)+(cosx-1/sinx)=0 Please help asap!!!!! PLEASE
*March 3, 2012*

**Trig**

prove(sinx/cosx+1)+(cosx-1/sinx)=0
*March 3, 2012*

**physics**

thank you!
*March 3, 2012*

**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 ...
*March 3, 2012*

**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...
*March 3, 2012*

**physics**

I don't quite follow
*March 3, 2012*

**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. ...
*March 3, 2012*

**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 ...
*March 2, 2012*

**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 ...
*March 2, 2012*

**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 = ...
*March 1, 2012*

**chemistry**

Current is applied to an aqueous solution of lithium sulfide. What is the cathode and what is the anode?
*March 1, 2012*

**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)
*February 29, 2012*

**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
*February 29, 2012*

**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
*February 29, 2012*

**chemistry**

Calculate the standard free-energy change for the following reaction at 25 °C. 2Au^3+(aq) + 3Ni(s) -->2Au(s) + 3Ni^2+(aq)
*February 29, 2012*

**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.
*February 29, 2012*

**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.
*February 29, 2012*

**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 ...
*February 28, 2012*

**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 ...
*February 28, 2012*

**Science **

Na subscript 2SO subscript 4 + CaCl subscript 2 produces CaSO subscript 4 + NaCl Please help me balance this equation and show your work
*February 28, 2012*

**MATH**

find the equation of the line tangent to f(x)=2x^3-x^2+1 at x=2. write in point slope form
*February 27, 2012*

**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 ...
*February 27, 2012*

**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 ...
*February 27, 2012*

**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
*February 27, 2012*

**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
*February 27, 2012*

**physics**

Thanks. the impulse is correct but the magnitude of the average force is not.
*February 27, 2012*

**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, ...
*February 27, 2012*

**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 ...
*February 27, 2012*

**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 ...
*February 24, 2012*

**English**

Does Victor have an obligation to the monster? Use evidence from Chapters 9-14 of Volume 2.
*February 23, 2012*

**physics**

P is to the left
*February 23, 2012*

**english**

Does Victor have an obligation to the monster in Frankenstein? Why?
*February 22, 2012*

**MATH**

√5sec²x-2secx=5 i have to solve this equation on the interval [0, 2π).
*February 22, 2012*

**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...
*February 22, 2012*

**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 ...
*February 22, 2012*

**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 ...
*February 22, 2012*

**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!
*February 20, 2012*

**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!
*February 20, 2012*

**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?
*February 20, 2012*

**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 ...
*February 20, 2012*

**physics**

thank you
*February 18, 2012*

**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 ...
*February 18, 2012*

**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.
*February 17, 2012*

**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?
*February 17, 2012*