Recent content by KillerZ

OK doing it with the substitutions: k = \frac{hA}{m_{Hg}C_{p,Hg}} and T = T_{Hg} \frac{dT}{dt} = k(T_a - T) \frac{1}{k(T_a - T)}dT = dt \frac{-1}{k}\int\frac{1}{(-T_a + T)}dT = \int dt \frac{-1}{k}ln|-T_a + T| = t + c ln|-T_a + T| = -kt + c -T_a + T = e^{-kt + c} T = ce^{-kt} + T_a...

Homework Statement I haven't done ODEs in a few years and I am trying to do this equation: m_{Hg}C_{p,Hg}\frac{dT_{Hg}}{dt} = Q Q = hA(T_{air} - T_{Hg}) T_{Hg}(t = 0) = 20 I need to find T_{Hg}(t=590) Homework Equations The Attempt at a Solution h, A, m_{Hg}, C_{p,Hg}...

I updated the previous post but it must have happened after you replied: Iref = 100uA R = 43K \frac{dIref}{dT} = \frac{1}{R}\frac{dR}{dT}(Iref) + \frac{1}{R}\frac{dVbe}{dT} \frac{dIref}{dT} = (1060 ppm/deg C)(100uA) + \frac{1}{43K}(-2mV/deg C) \frac{dIref}{dT} = 0.000000059 A/(deg C) I think...

I have a simple current mirror made of BJTs and the output current needs to be 100uA and I am trying to balance a resistors positive temperature coefficient (1060 ppm) with the negative temperature coefficient of the BJTs to temperature compensate it. I am sure that the fractional temperature...

The A is amps.

I am not sure if this is the right place to ask this. I am wondering how to convert to ppm/(deg C). I have a temperature coefficient I found and I am trying to convert the number to ppm/(deg C). The number I have is 0.000000059 A/(deg C) so do I just multiply it by 10^6 which gives me 0.059...

Homework Statement NASA would like to place a satellite in orbit around the moon such that the satellite always remains in the same position over the lunar surface. What is the satellite's altitude? Homework Equations T^{2} = \left(\frac{4\pi^{2}}{GM}\right)r^{3} The Attempt at a...

Ok I got it thanks for the help.

Ok I attempted this and here is what I got: KVL: iR + v = 0 iR + L\frac{di}{dt} = 0 \frac{di}{dt} = -\frac{iR}{L} -\frac{di}{i} = \frac{R}{L}dt -lni + C = \frac{R}{L}t I_{L}(0)=1 A -ln1 + C = \frac{R}{L}0 C = 0 -lni + 0 = \frac{R}{L}t 0 = \frac{R}{L}t + lni 1...

Homework Statement The switch has been closed for a long time. a) Current flowing through inductor. Voltage across it. IS any current flowing through the resistor. b) The switch opens at t = 0s. Find an equation for the inductor voltage as a function of time for t > 0. How long does it take...

I used this formula: v_{n} = v_{n-1} + a_{n}(0.1) which is what you said but would the position be: x_{n} = x_{n-1} + v_{n-1}(0.1) + (0.5)a_{n}(0.1)^{2} y_{n} = y_{n-1} + v_{n-1}(0.1) + (0.5)a_{n}(0.1)^{2} for every point?

Homework Statement I have some data from a lab conducted with a accelerometer to collect the acceleration and I am trying to figure out how to create a v vs t graph from the a vs t graph. When I create the a vs t graph in excel its very crazy looking because of the change in acceleration at...

Homework Statement Verify that the given functions form a fundamental set of solutions of the differential equation on the indicated interval. Form the solution. 4y^{''} - 4y^{'} + y = 0 e^{x/2}, xe^{x/2} Homework Equations...

I found the interval: as tanx = sinx/cosx cosx can not equal zero so the interval is: (-\frac{\pi}{2}, \frac{\pi}{2})

Homework Statement Find an interval centered about x = 0 for which the given initial-value problem has a unique solution. y^{''} + (tanx)y = e^{x} y(0) = 1 y^{'}(0) = 0 Homework Equations a_{i}(x), i=0,1,2,3,...,n is continuous and a_{n} \neq 0 for every x in I. The Attempt at a Solution...