Lv 1163 points

# paulinatran10

• ### A pendulum 1.60 m long is released (from rest) at an angle 30 degrees, mass 0.07 kg attached. Find tension at?

A pendulum 1.60 m long is released (from rest) at an angle theta=30 degrees, mass 0.07 kg attached. Determine the tension of the cord at lowest point theta=15 degrees.

Here's an image of the pendulum and the problem (It says earlier that the mass is 0.07 kg): http://i3.photobucket.com/albums/y92/musicis4fools...

I don't know why it says the "lowest point" and then theta=15 degrees because if it's at 15 degrees then it's not really at the lowest point right??? Can anyone help??

AND ALSO I already found that the velocity of the mass is 1.77 m/s at theta=15 degrees so you can use that for the setup. So far I have:

T - (0.07)(9.8)(cos15) = ((0.07)(1.77^2))/1.60

I solved it and got .7997 N, but that is wrong...... can anyone tell me what I'm doing wrong??? THANK YOU SO MUCH!

• ### What would happen to the peaks on a gas chromatogram if the gas chromatograph column was twice as long?

Would the retention time between the peaks be (twice as?) longer because it takes more time for the gases to reach the dector?? Or would it be shorter because the longer the column is, the more efficient the gas chromatograph is so it works faster?

• ### Calculate ΔG for this reaction at 25 degrees C when the pressures of NO2 and N2O4 are each held at 0.010 atm?

2NO2 --> N2O4

Calculate ΔG for this reaction at 25 degrees C when the pressures of NO2 and N2O4 are each held at 0.010 atm. Which way will the reaction tend to proceed?

I'm not sure which equation to use. Is it ΔG=RTlnP ?

• ### Determine the enthalpy for the partial combustion of methane to carbon monoxide from that of methane and CO?

Determine the enthalpy for the partial combustion of methane to carbon monoxide (2CH4 + 3O2 --> 2CO + 4H2O) from the enthalpy of combustion of methane (-890 kJ/mol) and the enthalpy of combustion of carbon monoxide (-283.0 kJ/mol)?

• ### Buffer at pH 5.0 that is 1.00 M in HX and 1.00 M in X-, Ka=1.0 x 10^(-5) M. Calculate effects of adding HCl..?

Here's the full problem:

Suppose you have a buffer at pH 5.0 that is 1.00M in HX and 1.00 M in X-, where HX is a weak acid with Ka = 1.0 x 10^(-5) M. Calculate the effects of adding 50ml of 1.0 M HCl to a 1 liter portion of this buffer and of adding 50 ml of 1.0 M NaOH to a separate 1-liter portion. What will the final pH be in each case?

THANK YOU TO ANYONE WHO CAN HELP!!!!!!

• ### What volume of 1.0M KOH must be added to 10 ml of 1.0 M acetic acid(CH3COOH) to give a pH of 5.0?

Ka for acetic acid = 1.8 x 10^(-5)

And is this mixture a good buffer? Why or why not?

THANK YOU SO MUCH IF YOU CAN HELP!!!!!!!!

• ### If CaCl2 is completely ionized in water, what does that do to the vapor pressure of it?

Ok the actual question is:

A solution of 22.0 g of CaCl2 in 100.0 cm^3 of water has a vapor pressure of 22.8 torr at 26°C. Why does this result support the view that CaCl2 is completely ionized to Ca2+ and Cl- in aqueous solution? (At 26°C the vapor pressure of H2O is 25.2 torr and the density of H2O is 1.00 g/cm^3 ; CaCl2 is non-volatile)

• ### The density of a certain gas is 2.94 g/L at 50°C and P = 1.00 atm. What is its density at 150°C?

In addition, calculate the molar mass of the gas, assuming it obeys the ideal gas law.

Can someone please help me with this problem?? I know you use PV=nRT but I have no idea how to get volume?? Thank you so much!

• ### Does the sum as n--> infinity of (4^n)/((5^n)-2n) converge or diverge?

I don't know which test I should use to solve this problem... help please? THANK YOU!

• ### The formaldehyde molecule has a π bond between the carbon and oxygen atom. Which of the statements isnt true?

The formaldehyde molecule has a π bond between the carbon and oxygen atom. Which of the following statements about this bond is not true?

A) This bond has two overlap sites that occur above and below the C–O axis

B) The figure-8 bond orbitals around the carbon and oxygen atoms actually extend to infinity but do have two overlapping areas

C) This bond is the result of the interaction of an unpaired carbon electron in the 2s orbital and an unpaired oxygen electron in the 2p orbital

D) Because carbon has four valence electrons and three of them were assigned lone electron sites in the three hybrid orbitals, there is one 2p orbital left in the carbon atom that participates in this π bond

I know the answer isn't A. But I'm still confused as to what the answer is...help please?? THANK YOU!

• ### What is the limit of n/(sqrt (n^2+1)) as n --> infinity?

I was thinking of doing L'Hopital's rule because i think its infinity/infinity form, right? but then i get stuck in this vicious cycle and I can't seem to find the limit.... help??!! THANK YOU!

• ### Find the surface area of the torus obtained by rotating the circle x^2+(y-b)^2=r^2 about the x-axis?

I have no idea on what the set up for this problem is. Can someone please help?? THANK YOU SO MUCH!

• ### How do you integrate 2dt/(-t^2 + 2t + 1)?

integral of 2dt/(-t^2 + 2t + 1)

• ### Help on set up for partial fractions to solve integral?

integral of (x+1)dx/((x^2+4x+8)^2)

How would you set up the partial fractions for this? And once you get the values for Ax+B and stuff, how would you integrate it? THANK YOU SO MUCH!!

• ### How do you use the comparison test to determine if this integral converges?

Integral from 1 to infinity: dx/((x^3 + 2x + 4)^(1/2))

THANK YOU SO MUCH IF YOU CAN HELP ME!

• ### How do you calculate empirical/molecular formula of vitamin C (molar mass =176.12g/mol)?

Vitamin C (molar mass = 176.12 g/mol) is a compound of C, H and O only. When a 2.000g sample was burned it produced 3.00 g of carbon dioxide and 0.82 g of water. Calculate the empirical formula and the molecular formula of vitamin C.

I know how to calculate the number of moles of CO2 and H2O but then I don't know where to go from there.... can someone please help?!? THANK YOU SO MUCH!

• ### If you spin x^2=4y around the y axis, what is the equation of the 3d figure?

The graph of x^2=4y in the xy-plane is a parabola, so when you spin it around the y axis it goes into the z axis... so what is the cartesian equation of the graph?? THANKSSS!

• ### Related rate problem involving position and velocity?

An object moving along a curve in the xy-plane has position (x(t), y(t)) at time t with (dx/dt)=cos(t^3) and (dy/dt)=3sin(t^2) for 0<t<3. At time t=2, the object is at position (4,5). What is the position of the object at time t=3?

I thought I needed to integrate the dx/dt and dy/dt but I can't do that by hand.... so I'm thinking there must be another way to get position without integrating? Can someone please help? THANKS SO MUCH!!