# Recent content by asdf12321asdf

1. ### Balancing redox reaction by half-reaction method

Homework Statement Balance the following equation by the half-reaction method. The reaction takes place in basic solution. Fe(OH)2(s) + O2(g) --> Fe(OH)3(s) The Attempt at a Solution All the other problems like this had 2 reactants and 2 products. What's confusing me about this problem is...
2. ### Difference between a kelvin and a celcius degree

Ok, will do. Thanks again for the help!
3. ### Difference between a kelvin and a celcius degree

It was right!! Thanks so much. I'm a bit confused by the answer though. Does 1K = 1C because of the fact that a change in 1 degree in both K and C is the same amount? Also, how am I supposed to know that they want 1K = 1C rather than 1K = -272.15?
4. ### Difference between a kelvin and a celcius degree

Homework Statement I feel stupid posting this but I am completely lost. This is a problem on my Chemistry textbook's website, which gives immediate feedback on whether you are right or wrong, and I am just unable to get it right. The question: What is the difference between a kelvin and a...
5. ### Doppler Effect

oh ok I figured it out thanks a lot
6. ### Doppler Effect

Homework Statement A stationary observer at a crosswalk hears an ambulance siren with an apparent frequency of 480 Hz when the ambulance is approaching. After the ambulance passes the apparent frequency is only 420 Hz. Find the speed of the ambulance. Assume v = 343 m/s for the speed of sound...
7. ### Angular momentum

Oh ok I actually see that equation in my notes, except it is marked as the parallel axis theorem, but I see that they are the same thing. Well I used the equation to find 'I' for the edge of the disk and then used L = Iω and got the right answer! Thanks a lot for all the help, it really...
8. ### Angular momentum

Ok thanks, I didn't realize L = r x p was only for that. I instead tried it with L = Iω and got .984 which is the correct answer. For part (b), I don't think we ever learned about Steiner's theorem. I don't see it in my notes and it is not in the index of my textbook. Maybe I'm just missing...
9. ### Angular momentum

Homework Statement A uniform solid disk of mass m = 4.50 kg and radius R = 25.0 cm rotates at 7.00 rad/s about an axis perpendicular to the face of the disk. Calculate the magnitude of the angular momentum of the disk (a) when the axis of rotation passes through the center of the disk, and...
10. ### Finding speed using energy equations

Thanks a lot! I changed the weights and then added the two equations and solved for vf and ended up with the correct answer. I was pretty clueless as to how to solve this question initially, but now I think I am starting to get it. Thanks again!
11. ### Finding speed using energy equations

Ok I got that Yf of mass2 is 2. And if I write the equation for each mass I get: mass1 (.5)(18)(vf)² + (18)(9.8)(0) = (.5)(18)(0) + (18)(9.8)(4) mass2 (.5)(18)(vf)² + (18)(9.8)(2) = (.5)(18)(0) + (18)(9.8)(0) Is that right? Does that help me at all?
12. ### Finding speed using energy equations

Homework Statement Two masses are connected by a light string running over a frictionless pulley as shown below. The system is initially at rest and the incline is frictionless. If m1 = 10.0 kg, m2 = 8.00 kg and the incline makes a 30o angle from the horizontal, use energy methods to find the...
13. ### Finding distance with the conservation of energy equation

Oh wow, thanks a lot. I changed the m in Uf to .15 and then got 16.6m which is the correct answer. It's unfortunate I've spent all this time on this problem due to this small error, though it's reassuring to know I was doing it the right way at least. Thanks again!
14. ### Finding distance with the conservation of energy equation

Homework Statement 3. A baseball (m = 0.150 kg) is thrown with an initial speed of 30.0 m/s at an angle of 37.0 degrees from the horizontal at y = 0 m. (a) Find the initial KE of the ball. (b) Use conservation of energy (not kinematic equations) to find the maximum height reached by the ball...
15. ### Force of a roller coaster track on a car

Thanks for the help! I realized I had to also add the normal force when it was at part a. I was able to figure out part b and c based on that information.