Recent content by Donna14

Homework Statement Doing my homework I came across the question: why it would be better to have styrofoam on the inside of the house And why it could be better to have it on the outsideThe answer is The steady state will be the same for both but inside: warm and cold quickly Outside...

I don't even know where to start!

Homework Statement See attachmentThe Attempt at a Solution Im not sure how to solve c and d...

But P x A= force isn't it? So you say (Pbelow-Pabove)xA=mass? Or mg? And I haven't got any other info about P... I have substituted (Pbelow-Pabove) for mg/A and my result seems to be correct now. But I am not sure why I can say that the difference of P is this...

P1-p2=1/2ρ(v22-v12) But I don't know the pressure and I don't understand what to do with drag and lift force? And do I have to use the given engine power? Sorry this is completely new to me...

But I am stuck on how to continue... Can you please help me a bit?

Homework Statement See attachment Homework Equations Maybe lift force = ClρAv2 A=area Cl= lift coefficient= 0.3 ρ= air density V=air speed but don't know which one it represents... Under or below wing or average? And the bernoulli equation seems to be needed as well... The Attempt at a...

Homework Statement See attachment Im struggling with b and c. I did an attempt, but really don't know if it is correct. Homework Equations The Attempt at a Solution See attachment

Can you help me now the attachment is there? Thanks!

Homework Statement See attachment In the first place I don't understand why you can just say: dV/V = ln(Vd/Va) ( was given in lecture slides) And I am not sure if my attempt to the solutions is any good... Hope Someren can help me a bit with b and c Homework Equations The...

I got it! Thank you so much!

I really appreciate your effort! I understand now that J is the same, but still don't know what to do with the to equations... Sorry!

But won't the flow through styrofoam be different from the flow through brick as they have a different k? And one Goes from inside to the brick wall and the other from the brick wall to outside. I understand that there is also a 'total' flow from into outside. And how do I combine these 2...

I thought that I had two different J as they both represent a different number... Im really not sure how to continue from here... I am sorry... Can you give me a hint?

Thanks for your response. Js=-ks*A*((Tinside-Tw)/thickness styrofoam) Jb=-kb*A*((Tw-Toutside)/thickness brick wall) How do I now eliminate Tw?