# 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

i see - thanks for the help everyone! makes sense. i did get complex confused with irrational.
3. ### 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...
4. ### Can you have a triple replacement reaction?

thank you for the reply. just to add to the question, hypothetically if you add NaCl and KOH you should get NaOH and KCl, right? but then if you add a 3rd reactant (say Ca(NO3)2) why doesnt it then continue to react with the NaOH and KCl that have now been created from the first reaction...
5. ### 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...
6. ### 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...
7. ### Free body diagram (centripetal force)

but i thought the sum of all the forces has to equal the net force (ie, centripetal force) - how come on my diagram those force vectors dont add up to the centripetal force vector?
8. ### Free body diagram (centripetal force)

yes but then how do those add up to the centripetal force? on the diagram it doesnt add up
9. ### Free body diagram (centripetal force)

forces vertically would be weight and normal i think. im trying to draw my diagram from a birds eye view. and i cant figure out which way friction would point or if there is another force too. my logic is that if there is a forward force (engine force?) there would have to be at least one...
10. ### 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...
11. ### 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...
12. ### 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?
13. ### What is the relationship between Kc and Kp?

bump: found one correction i think: for A: I=0, C=x, E=x for B: I=2, C=-2x, E=2-2x but still cannot connect these values (which are pressures) to a given Kc value without temperature. what should i try next?
14. ### Determining intial rates of reaction

i think i solved it: rate = k[C2H5Br ][OH] correct?
15. ### How to find equilibrium pressure when volume changes

where did you get K = 5.33? and is that Kp or Kc? and why isnt Peq for NO2 = 1.2 + 2x? where did the 1.2 go? thanks for all your help.
16. ### How to find equilibrium pressure when volume changes

still a little confused. does this mean the partial pressure does not change as volume changes? i dont understand why the number pf particles increases too - where do these extra particles come from? and therefore, if volume and pressure changes do not change equilibrium partial pressures...
17. ### 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...
18. ### What is the relationship between Kc and Kp?

ok well how do i get Kp from Kc if no temperature is given? A <--> 2B initial partial pressure of A is 0 and initial partial pressure of B is 1 atm. they ask to find the equilibrium partial pressures of A and B and they give Kc value. im pretty sure this is an ICE problem for A...
19. ### What is the relationship between Kc and Kp?

what about the 2nd question? what i think needs to be done is to assume the number of moles for SO3 and NO is the same because both products are made in equal quantities at equilbrium - is that the correct assumption? then i can plug all the numbers into the Kc equation and solve from there?
20. ### 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...
21. ### 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...
22. ### Tension rope swing problem

another bump - still confused. at the bottom of his swing, how does the centripetal force, tension force and his weight relate to each other? i know weight points up and centripetal force points towards the middle (therefore up), but tension? i think it points up as well so would the...

anyone?
24. ### Tension rope swing problem

i konw but how do i put it into the calculations? so far all i figured out was the centripetal force? how does the centripetal force, tension and his weight relate to each other at the bottom (when hes going 8 m/s)?
25. ### 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...
26. ### Net work

but if i know the distance the box traveled i could also multiply that by ma (net force) to get work, right?
27. ### Net work

so basically you can take the net force (ma) in the same direction as its moving and then just calculate that distance to multiply to get the net work? so gravity has no real part here?
28. ### Net work

would it be: (10kg)(5 m/s2)(5m) = 250 J is that right?
29. ### Net work

thanks. what if the quesiton did say he was accelerating up the slope with a = 5 m/s2? would that change the answer then?
30. ### 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...