By how much does each spring stretch?

[minitorpedo]

and doesn't the force from friction need to be factored in too?

 

[Hootenanny]

and doesn't the force from friction need to be factored in too?

Argh! Dammit, I knew there was something that I'd left out, couldn't figure out what though! You need to factor in the kinetic friction between the lower block and the table;

$$F_{applied}-F_{spring}-F_{friction} = 0$$

Please accept my apologies, long day. I guess I should go settle down and nice single malt and the West Wing

 

[minitorpedo]

haha, its ok, so its F_applied = Fspring+Ffriction
F spring is what we found, and Ffriction is mgu?

 

[Hootenanny]

haha, its ok, so its F_applied = Fspring+Ffriction
F spring is what we found, and Ffriction is mgu?

Yes you're correct. However, you should note that m is the combined mass of both blocks (i.e. 15kg + 30kg). Do you understand why?

 

[minitorpedo]

yes, i got it right. Thank you so much! i see that ur quote is from seneca, I am guessing that's Seneca High School in the lenape regional district, becasue I am from lenape. well once again thank u

 

[Hootenanny]

yes, i got it right. Thank you so much! i see that ur quote is from seneca, I am guessing that's Seneca High School in the lenape regional district, becasue I am from lenape. well once again thank u

No problem, it was my pleasure, again I apologies for my fatal error . Actually, its from a first century philosopher called Seneca the younger, whom perhaps the High School was named after.