Recent content by henrco

I have question that has been troubling me and I was hoping someone may be able to help me. I've always thought the Hubble classification of galaxies was a bit subjective. I was recently looking at some images online of galaxies and I was wondering how you might objectively observe and compare...

The thin shell would collapse to (r - width of shell), assuming that the entire shell burns off. I am to assume initial distribution as uniform. I understand that the GPE will will be different an initial and final radii. However I don't understand. 1) Is there a way of working out what the...

Homework Statement Suppose that a 15 M(solar masses) star finally runs out of nuclear fuel in its core and undergoes a Type II supernova explosion. You are going to analyse the energy budget, calculating all the quantities in Joules. a) Estimate the amount of gravitational energy that would be...

Thank you.

Thank you for the prompt reply. The lower the value for apparent magnitude the brighter the object appears. So I would say you subtract the change in magnitude. So 14.2 - 14.87 = -0.67

Thank you for the response and guidance. i) I saw my mistake regarding powers of 10 and corrected it. ii) The change in magnitude comes out to 14.87 Finally I need to calculate the change in apparent magnitude, the current apparent magnitude is 14.2 and the change in magnitude is 14.87...

Hi, I haven't posted an Astronomy question before. I did see some Astronomy questions in this section so I posted it here. But if it's in the wrong place, for future reference, please let me know where it should be posted. 1) The first problem I need guidance on is the value I have obtained...

Excellent, thank you.

Hi, Could i please get advice on this problem and confirm that my approach and solution are correct? Thanks in advance. 1. Homework Statement An enemy space rocket traveling at speed 0.8c towards the planet Zog fires a missile in the direction parallel to its own path. Relative to the rocket...

Thank you for this. Clearly my brain decided not to work earlier... Since the rocket travels at 83.39% of the speed of light, or 83.39c Then the distance traveled will be 6.62 x 83.39/100 = 5.52 light years.

Understood, thanks for the response.

So you are saying that W should be negative. Therefore the equation should become: -Q+(-W) = ΔU (as Q is negative due to heat loss) That would mean the answer to this question would be : ΔU = - Q + (-W) = - 3.69 x 10^3 + (-1053.5) = -4743.5 J ΔU = -4743.5 J Which isn't the correct answer.

Thank you all for the responses but I got a bit confused. However it's clear that this confusion was just waiting in the background to emerge... so thanks, this has been very helpful. Hopefully, the following is correct. ΔU = Q + W (I'm go to use this formula as I find it more intuitive). Q =...

Thanks for your reply SammyS but the 'penny' hasn't dropped for me yet. To answer your question, light would travel 6.62 light years in 6.62 years. However the speed of of the rocket is 83.39% speed of light. So I'd expect the distance to be larger than 6.62 light years but certainly less than...

Thank you both. I went back and did some more reading! In this example the system is giving off heat so, so Q should be negative. Also my understanding, is that because the work is done to the system, W should be positive. Calculate the work done. W = P.ΔV = 1.3 atm x (20 - 12) L = 10.4 L atm...