TwinkleBat

A 75 kg passenger is seated in a cage in the Sling Shot, a carnival ride. Giant bungee cords are stretched as the cage is pulled down, and then they rebound to launch the cage straight up. After the rapid launch, the cords go slack and the cage moves under the influence of gravity alone. What is the rider’s apparent weight after the cords have gone slack and the cage is moving upward?

I thought it would just be mass * gravity (75 kg * 9.8 m/s*2 = 735 N), since it says "the cage moves under the influence of gravity alone", but it marked me wrong. Unless the apparent weight = 0 N, because the only influence is gravity? Please help me understand!

"A car traveling at velocity v takes distance d to stop after brakes are applied. What is the stopping distance if the car is initially traveling three times as fast? Assume that the force due to braking is the same in both cases.

Draw force, acceleration, velocity, and position vs. time graphs for both situations. Identify known and unknown quantities with variables and label graphs. Determine the unknown."

So, I think I have the graphs. Basically, since we're assuming its the same car, mass is the same. If force is the same (given above), then acceleration is the same, i.e. F = ma. For velocity, one line starts three times higher than the other and they have the same slope (since acceleration is the same) and end at 0. Position I think both would be curved and both would be starting in the same place, but one would end further out than the other along the time axis at v = 0. Make sense?

I also think I have the knowns and unknowns. What I don't understand is how to determine the unknown (i.e. the stopping distance). I know it'll be in a ratio, and some random thought is suggesting that three times the velocity equals nine times the distance, but I have no idea if that's true or where it comes from. Please set me right and explain your answer.

Sorry this is so long. Thanks for reading and considering.

P.S. - I know from looking around google that one answer to use involves work and the equation F*d = 1/2*m* v^2, but we haven't done this yet, so I'm kinda at a loss here.

Alkyne: Cyclohexane-CC-CH2-CH3 (CC is triple bond)

Reagents: 1) 2 Na, NH3

2) D2, Pd

Things I know:

- alkyne to alkane through alkene

- all 10 carbons of reactant will be in the product species

- not cyclohexane-CH2-CH2-CH2-CH3

If important, show all atoms on chirality centers.

Please help! (Also, if you would, tell me how you got the answer you got.)

IR: 2300-3200, 1710, 1600;

H1-NMR: 2.9--2H--triplet, 4.1--2H triplet, 6.9--3H--(crazy quartet looking), 7.1--2H--(crazy triplet looking), 11.7--1H--singlet/broad.

I think that is a 1,4-disubstituted benzene ring (C6H4) based on the two triplets at 2.9 and 4.1 and that there's a COOH group somewhere, given the IR. The crazies around 7 are screwing with my head. I've been doing fairly well with this NMR stuff otherwise :(

Please help with the rest of the problem!

In chem lab, I combined 10mL of 4% borax solution with 10 drops of methyl red indicator and titrated it with 3.0 M H2SO4. I found out that 0.4mL of H2SO4 caused the solution to change color (yellow to red). The question asks me to calculate the concentration of the borax solution. I'm not sure how to set up this problem. Any help would be much appreciated.

Other:

Molar mass borax = Na2B4O7·10H2O = 381.37 g/mol

Expected concentration borax = 0.105 M (I need the empirical answer from my data. This is only for calculating percent deviation, which I know how to do.)

I was at a blood drive the other day, and they have one of those machines that measures your blood pressure, pulse, and temperature by just pushing a button. This is supposed to eliminate human error, as I understand it. When I was measured, my bp and temp were normal, but my pulse was 115. They waited 15 minutes, tried it again, and I was at 122. They waited another fifteen minutes and tried it again, and I was at 105. I was very confused because during the wait time, I had taken my radial and carotid pulses manually and got 76. I told the person screening me this, and I asked her to take it manually immediately after the last reading of 105. She got 72, about a minute after the machine got 105. She told me that the machines were slightly more accurate, but that this discrepancy was much more than average, and that a 33 point drop in a minute was highly unlikely naturally. She got her supervisor, who said that they had to use the machine readings, the machine was calibrated that morning, and that nobody else had raised any concerns. I was deemed ineligible to donate that day. I am very curious to find out why the machine and palpation results were so different, because I do want to donate blood again. I have before, but mostly they've taken my bp and pulse manually, and every single time, I have been well within normal limits.

Additionally, I have never been diagnosed with a heart problem and I am not on any medication. I do take a daily vitamin. I am also within a healthy weight range for my height, and in my mid-twenties.