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HNQ
1:52 AM
1
Q: Why rocket equation?

Curious kidwhile deriving rocket equation we find change in momentum of rocket and this is the result: $$Δp=MΔV+Ve ΔM$$ from here we divide this by time to calculate force and since no external force(freespace) is acting we get: $A=Ve ΔM/M $ ($A $ is acceleration of rocket) And now we integrate this with t...

 
HNQ
2:17 AM
1
Q: The difference in path lengths for waves in the double slit experiment

user110391 Fig.1 I don't quite understand the diagram, because it shows $L_1$ and $L_2$ as parallel, even though they are supposed to meet at the same point. I believe the idea is that $\Delta L$ approaches $d \sin \theta$ as the distance to the screen increases. However, that is not exactly the case, and...

 
 
13 hours later…
HNQ
3:01 PM
1
Q: "Natural frequency" seems to be a poorly defined concept

FraïsséPer wikipedia: natural frequency, also known as eigenfrequency, is the frequency at which a system tends to oscillate in the absence of any driving force. Let's take a wine glass as an example. The wine glass sits on a table, it is not visibly moving. But since natural frequency exists, therefore...

 

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