# Search results

1. ### A point moves along the curve y=2x^2+1

A point moves along the curve y=2x^2+1 in such a way that the y value is decreasing at the rate of 2 units per second. At what rate is x changing when x=(3/2)? Ok here's what I've done... Dy/dt=(4x)(dx/dt) -2 = (4*3/2)(dx/dt) So dx/dt=-1/3 (ie decreasing by 1/3 units per second) First, is...
2. ### Question on the logic of rational roots theorem

this is not a homework question, but rather I feel like there is a contradiction in the theorem and just want clarity. I know the theorem is correct so Im looking for help in where the mistake is in my logic. take f(x) = x^3 + x^2 - 4x- 7 the rational roots theorem says if there are any...
3. ### Can you have a triple replacement reaction?

is it possible to have a triple replacement type reaction? I know of single and double replacement but what if you mix sodium carbonate, magnesium hydroxide, and potassium sulfate all together (this is all made up just for an example). would all the different ions mix to form all possible...
4. ### Le chatliers principle and solids

im pretty sure i know the answer but want to be sure. if you have a reaction such as : A(g) + B(g) --> C(g) + D(s) and you increase the concentration of A, the reaction will shift to the right. and i know the concentration of B will decrease and C will increase. but what about D. im pretty...
5. ### Free body diagram (centripetal force)

Homework Statement simple question really - how do you draw the free body diagram for a car going around a corner? Homework Equations n/a The Attempt at a Solution i know the net force, the centripetal force, points towards the middle. i have an engine force pointing tangentally...
6. ### Determining OH- and pH of a weak base

the question is simply to determine the [OH-] and pH of a solution that is .210 M in HCO3- first of all if i can get [OH-] then i can easily get pH by converting [OH-] to [H+] and then doing the -log[H+] so that part is easy. i just cannot get [OH-] what i did was first write the...
7. ### Calculating concentrations

question states: Calculate the concentration of all species in a 0.240 M C6H5NH3Cl solution. first of all how do i know what the reaction is? secondly to i need to know the Ka value for the dissaciation for this - why isnt it given?
8. ### How to find equilibrium pressure when volume changes

question: an equilibrium mixture contains N2O4 (P=0.27 atm) and NO2 (P=1.2 atm) at 350K. the volume is doubled at constant temperature. calculate the equilibrium pressure of both at new equilibrium. what i know: when you double volume, pressure is halved and le chatliers principle says the...
9. ### Determining intial rates of reaction

problem states: C2H5Br + OH- --> C2H5OH + Br- if the reaction mixture is .16 M C2H5Br and .26 M OH-, then what is the intial rate of reaction at 85 degrees. they also give a table of different temperatures and the associated k values at each. i also determined the activation energy...
10. ### What is the relationship between Kc and Kp?

what is the relationship between the equilibrium constant Kc and the equilibrium pressure constant Kp? I am given many questions that either give Kc and ask for partial pressures of gases or vice versa. what is the best way to approach these questions? another question states given this...
11. ### Tension rope swing problem

Homework Statement a man swings from a rope which is 10 feet long. his mass is 80 kg and at the bottom of his swing, he is going 8 m/s. The max tension the rope can take without breaking is 2000 N. Does he make it? Homework Equations Fc = mv^2/r The Attempt at a Solution...
12. ### Net work

Homework Statement a man pulls a 10 kg box up an incline at a constant speed to a vertical height of 5 m. what is the net work being done? Homework Equations w= fd The Attempt at a Solution i know in the plane perpendicular to the surface there is no net work done because all...
13. ### Impulse/momentum/collision question

Homework Statement basically a cue ball is struck by a cue, and that ball travels (without friction) and hits another ball (which isnt moving initally). they give all the masses and the impulse of the cue hitting the first ball. they tell us its an elastic collision. Homework Equations...
14. ### Impulse/momentum concept questions

Homework Statement (hopefully all can be read) Homework Equations p = mv impulse = m(change in v) The Attempt at a Solution Top Left: My initial guess is they should all be the same since all cars on the roller coaster feel the same affect of gravity for the same distance...
15. ### Finding spring balance readings (newtons)

Homework Statement Find the readings on each of the balances in these 4 situations (strings are massless and incline is frictionless): (sorry about the photo - dont know how to fix it) Homework Equations F=ma, W=mg The Attempt at a Solution 1) Seems easy enough. Im pretty...
16. ### Elevator problem

Homework Statement Quite simply, you are moving up at a constant speed in an elevator and you are to compare what a scale reading would be at this constant speed (given to be 700 N) to when you slow down to a stop. Homework Equations Fnet = ma The Attempt at a Solution Clearly...
17. ### Trig limit question

Homework Statement evaluate the limit as x goes to 0 of: tan(4x^2)^2/(3x^4) (thats suppose to say the tangent squared of 4 x squared all over 3 x to the 4th) Homework Equations n/a The Attempt at a Solution the only trig limit stuff i know is the limit to 0 of sinx / x = 1...
18. ### How to derive the derivative formula of arctan x?

Homework Statement basically what the topic states - derive the formula for the derivative of arctan x. Homework Equations d/dx (arctan x) = 1/(1+x^2) The Attempt at a Solution strange question because we already know the answer. but im not sure how to start this. i know...
19. ### Find volume of a solid

Homework Statement tbe base of a solid is the region between y=x and y=x^2. find the volume of the solid if cross secions perpendicular to the x axis are isoceles right triangles with hypotenueses in xy plane. Homework Equations n/a The Attempt at a Solution honestly i cannot...
20. ### Determining best method for volumes?

Homework Statement No specific question but what is the best way to determine which method is the best for solving for volumes (using integration) of shapes as they revolve around axis/lines. disk method? washer method? shell method? other? what exactly do you look for that may hint...
21. ### Solving for derivative of e^x using limit definition

Homework Statement I want to solve for the derivative of e^x using the limit definition. Homework Equations http://www.math.hmc.edu/calculus/tutorials/limit_definition/img10.png [Broken] The Attempt at a Solution obviously the derivative of e^x is itself, so i konw the answer. i...
22. ### Vertical velocity and integration

Homework Statement a list of data is given for a seat on a ferris wheel that is traveling in a circle. the data is time vs its vertical velocity. the question is to estimate the diameter of the ferris wheel. Homework Equations n/a The Attempt at a Solution what i did was...
23. ### Integral problem

Homework Statement how do you integrate (xcox)dx Homework Equations n/a The Attempt at a Solution ive gone through so many ways that ive learned how to integrate problems and i cannot figure this one out. can someone just give me a hint on how to start it? thanks. (i have a...
24. ### Inertia problems

Homework Statement 1) A large 14 kg roll of a paper (radius = 19 cm) rests against the wall and is held in place by a bracket attached to a rod through the center of the roll. the rod turns without friction in the bracket and the moment of inertia of the paper and the rod about the axis is...
25. ### Illustrate an integral expression?

Homework Statement let f(x) = ln of the square root of (4x-16) using the definition of ln x, write and illustrate an integral expression for f(5) Homework Equations n/a The Attempt at a Solution im confused on even what its asking. what does it mean to illustrate an integral...
26. ### Chemistry questions

Homework Statement 1) how do you know if a double replacement reaction occurs or not? 2) how do you predict products in decomposition and synthesis reactions? 3) do you include metals in net ionic equations? 4) are the exceptions to electron configurations limited to only Cu and Cr...
27. ### Couple of integrals questions (and with limits)

Homework Statement a) integral of e^(x^2) (ie, integral of e to the x squared power) b) integral from -1 to 6 of the square root of 3 plus the absolute power of x (sorry i dont know how to make it look nice on these forums...havent learned the code for it yet) c) this one is...
28. ### How to interpret integrals of graphs

Homework Statement no specific question but generally they give you a graph of f(x) (with semicircles, lines, above/below x axis - could be anything) and say that g(x) is the integral from 0 to x of f(x). then they will ask things like: 1) g(2) 2) find relative min/max for g(x)...
29. ### Definite integral

Homework Statement if the integral from 0 to 4 of f(x) = -1 then what is the integral from -2 to 0 of x[f(x^2)]? Homework Equations n/a The Attempt at a Solution my first instinct is that this is an even/odd definition of an integral problem. the x squared in the function...
30. ### Work done by tension question

Homework Statement A simple pendulum, consisting of mass m and a string, swings upward making an angle X with the vertical. What is the work done by the tension force? (answer in terms of mg) Homework Equations W=Fd The Attempt at a Solution What I need to do is solve for the...