Recent content by Wolvenmoon

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    What Speed Limits Apply on a Wet Banked Roadway?

    Ah! I had a longer post reworking the problem the wrong way! I started digging through Google and found this site: http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/carbank.html Their diagram makes things make more sense. However, I'm still not crystal clear on this and have spent an...
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    What Speed Limits Apply on a Wet Banked Roadway?

    Homework Statement Consider a wet banked roadway, where there is a coefficient of static friction of 0.30 and a coefficient of kinetic friction of 0.25 between the tires and the roadway. The radius of the curve is R=50m A: If the banking angle is β=25∘, what is the maximum speed the automobile...
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    How to solve a velocity problem as an initial condition problem

    Thank you! That does provide the correct answer in either case (t=4.76, then that can be substituted into v(t) = -29.6m/s!) I'm glad to know it was something simple.
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    How to solve a velocity problem as an initial condition problem

    I believe a bad guess. The initial position is y=0m (the level of the roof), the ball ends up at y=-30. That probably should be a zero.
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    Change in velocity when given a graph that shows time and acceleration

    I come from Google! If you draw out the graph you might notice that your equation a_x = 1*t+2. Drawing lines at x=4.5 and x=7.5 gives you a_x values of 6.5 cm/s^2 and 9.5 cm/s^2. The area of a trapezium can then be calculated by the integral of (1t+2)dt from the lower bound 6.5 to the upper...
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    How to solve a velocity problem as an initial condition problem

    Homework Statement A small rock is thrown vertically upward with a speed of 17.0m/s from the edge of the roof of a 30.0m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected. Homework Equations Acceleration...
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    ( easy ) Powering LEDs off of triple A batteries

    Since I'm already $20 in if I do this, anyone know of any 1.5-4.0V rechargeable power sources that would take a USB plug as a charger/tether so I could switch between battery power and 'plugged in' whenever I needed to? Otherwise, it's rechargeable alkalines ( I'm afraid to try out...
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    ( easy ) Powering LEDs off of triple A batteries

    Well, whatever I do I have to wear as part of a headset. I've heard of rechargeable alkaline batteries, but I'm skeptical as they seem to be niche market items. Do you have any specific resistors in mind from any specific stores? I'm going to attempt to run the LEDs off of 1.2V first, but if...
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    ( easy ) Powering LEDs off of triple A batteries

    So, are there any easily rechargeable, interchangeable 1.5V power sources I could get? These LEDs will be detected by a wiimote mounted over my monitor and will function as a head mouse for me. It's sort of important that they be as close to their maximum brightness as possible. I'll be able to...
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    ( easy ) Powering LEDs off of triple A batteries

    Any thoughts on a rechargeable 1.5V power source? Should I bother trying to step the voltage up on rechargeables or should I consider putting two batteries in series and using resistors from there? I seem to remember something about rechargeable batteries having a voltage drop as they...
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    ( easy ) Powering LEDs off of triple A batteries

    Okay, this is obscenely easy and that's why I'm confused on it. http://teachwithtech.com/Full-Product-Listing/Vishay-TSAL6400-10-Pack-p21.html What I'm trying to do is power two of those LEDs off of a single triple A battery, if at all possible. I don't know what the specifications mean. I...
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