Recent content by crom1

Homework Statement Discrete time causal LTI system has impulse response h(n) = (-1/2)^n, n≥0. a)Find transfer function of given system. b)Find frequency characteristics of system. c) Find response for u(n) = μ(n)-μ(n-4) The Attempt at a Solution a) Either from definition, or from table...

Homework Statement continuous time LTI system is given with differential equation y'(t) + 5y(t) = 10u(t) a) Find transfer function of system and determine is it stable or not. b)Find frequency characteristics (amplitude and phase angle) of given system c) Find impulse response using Laplace...

Simple harmonic motion? Yes, I see that this is the same type of equation. We didn't yet talked about harmonic motion in my physics course (We did in high school but on that level) so don't be suprised by my ignorance :D , but one more question : when I get x in terms of t, how should I find t...

I'm currently learning this on my own, so I might miss some obvious and basic stuff. Do you mean like this $$ \frac{d^2x}{dt^2}= -cx+d $$ (Did you meant some kind of substitution y=x-d/c or? ) EDIT: I did get t=-1/c ln|-cx+d| but I don't have x so that probably not good...

velocity won't change, and acceleration has to be negative in order to v be 0 at some moment? Okay, but how do I calculate velocity when acceleration is changing and I don't have velocity in terms of t ? I tried something like this: $$ a=g \sin \alpha - \mu g \cos \alpha = g \sin \alpha-0.1 g...

If the part with F_1=F_{fr} is wrong, I don't think there's a point in posting my working before I realize when will the box stop. Hmm, can you show mistake in my reasoning? Since v_0=0 , the box will stop when v=0 , and v depends on acceleration, so acceleration has to be 0 , so F{res}/m=0 ...

Box is sliding down the slope with angle 30 , and v_0=0. Because coefficient of friction is $$\mu=0.1x$$ where x is distance covered, the box will stop before reaching the end of a slope. Find the time needed for a box to stop. I get $$F_1=G \sin \alpha , F_{fr} = \mu \cdot G \cos \alpha$$...

Thanks to both of you. I only have to find effective value, and I get the right solution (10V).

I never seen this kind of problem before,so I am not sure what to do. If the above formula is supposed to be used, then on the first part of interval (where i is increasing) i get u_m=5V,and on the second part I get u_m=20V but I guess in different direction? I am not sure what to do with them.

Homework Statement Find effective value of voltage between points 3 and 4. The diagram on the right shows behaviour of current i. Homework Equations [/B] $$ u_M= M \frac{di}{dt} $$ The Attempt at a Solution [/B] I tried with formula above, didn't work for me. I haven't seen how to solve...

I meant why Zt is independant of that R, but I get it now,thanks.

Yes,I do get Zt=10 ohms. One more question though, how do I justify the fact that I ignore the resistor R next to voltage source in the first picture?

You're right. I now get P=64-j64, do I now just take real part to get P=64?

Z=Zt=4+j4

I forgot to say U=100 V , R=XL=Xc=10 ohms. Can I conclude since this is wheatstone bridge , and R^2=Xl*Xc, that the I_N=0? But still, I do get for thevenin voltage for A=50+j50, and B=50+j50,i.e. Ut=0? How do I found impedance now when both of these are 0?