Recent content by Pochen Liu

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    Calculate internal temperature and energy changes

    Question (These are incorrect values) Attempt I used and then found the respective change in temperature. However for the last question I have no idea, do I sum up the net change in temperature and use But then what is the work and how do we figure it out?
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    Circular loop of wire is concentric with a solenoid

    I got 0.00054996 Ohms (Which I hope is correct??). Thank you so much!
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    Circular loop of wire is concentric with a solenoid

    Is N = 1? Because we have only a single ring? And I chose A to be the cross section of the area because that's what the equation for B is. The magnetic flux density through the solenoid as it's within the ring, but we treat the ring like a solenoid, so N = 1.
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    Circular loop of wire is concentric with a solenoid

    Judging by this, A = pi * 0.0207^2 (Solenoids radius right?) And n (Not N) = 8230/m
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    Circular loop of wire is concentric with a solenoid

    To confirm, is this what you meant? I have played with the equations a little. Also, n is the density of coils/m However I am not provided with the length of the solenoid?
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    Circular loop of wire is concentric with a solenoid

    Sorry I don't follow, I can find the rate of change of these with regards to time, however I don't see anything I can do it with
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    Circular loop of wire is concentric with a solenoid

    Question: In Figure (a), a circular loop of wire is concentric with a solenoid and lies in a plane perpendicular to the solenoid's central axis.The loop has radius 6.13 cm. The solenoid has radius 2.07 cm, consists of 8230 turns/m, and has a current i_sol varying with time t as given in Figure...
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    How can I use KVL and KCL to find the potential differences in this circuit?

    In the figure ε = 9.89 V, R1 = 1150 Ω, R2 = 2890 Ω, and R3 = 4940 Ω. What are the potential differences (in V) (a) VA - VB, (b) VB - VC, (c) VC - VD, and (d) VA - VC?What I've tried I have derived the equation ε - i1R1 - i2R2 = 0 where i1 is the current running through R1 and vice...
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    Difference between time / length equations for time dilation

    What is the difference between time dilation (t is the stationary reference frame) t = Description: If two successive events occur at the same place in an inertial reference frame, the time interval 􏰋t0 between them, measured on a single clock And this equation for time, if we take t' as the...
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    Extra speed necessary to orbit at 970 km

    It was accelerated over the course of 3.5km to reach 7000 m/s. Which is unrelated? we assume it leaves from the surface of the Earth not 3.5km out
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    Extra speed necessary to orbit at 970 km

    E is conserved as the engine is not on as it leaves at 7000m/s till it reaches 970km. Once it hits 970km the engine will turn on and E is not conserved, however that is not our concern. We only need to determine how much extra speed it needs once its 970km? If I'm wrong, how else can we go...
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    Extra speed necessary to orbit at 970 km

    So using conservation of energy where v0 = 7000 m/s $$ K_{i} + U_{i} = K_{f} + U_{f} $$ $$\frac{1}{2}mv^{2}_{0} - \frac{GMm}{R} = \frac{1}{2}mv^{2} - \frac{GMm}{r}$$ where R = the radius of the Earth and r = the distance from Earth's center plus the height its orbiting $$v =...
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    Understanding resonance in a spring

    I have the equation $$\frac{d^2y}{dt^2} + 5y = 0$$ where I've worked out $$y = Acos(\sqrt5t) + Bsin(\sqrt 5 t)$$ $$y'' = -5Bsin(\sqrt 5 t) $$ using $$y = e^{\lambda x}$$ and using y(0) = 0 (the spring is released from equilibrium) so an external force $$Acos(\omega(t - \phi))$$ is applied so...
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    What are the steps for calculating the center of mass of this object?

    I see, so how would you put this formally? I understand that it's the force of gravity from its mass, but why does this work?
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    What are the steps for calculating the center of mass of this object?

    What are the steps to calculating the center of mass for this object? I don't want a numerical answer just the theory. I understand I need to calculate COM for all axis, we know in the Y axis it's dead centre because of symmetry but I don't know how to do it for the others. A hint would be...
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