Does the acceleration cancel out?

[Medgirl314]

m2 g - Mm1 g = 0

I think I see it now. If we divide both sides by g, they cancel out. m2 - Mm1 = 0
We already have the equation set to zero. Do I just fill in the numbers and use the quadratic formula?

 

[BvU]

A little bit yes and a hefty no. You really made three chaps happy by typing m2 - Mm1 = 0. You can make them even happier by typing m2 = Mm1 (because then you "have solved for m2"). No need for a quadratic formula ! Or "the"quadratic formula. Shudder.

There is some latest news flash from post #4 that m2 is not 13 kg but 12 kg.

And M = 0.25 as steadfast as ever.

(<Alt>"230" µ is, I am sorry to say, not TeX but a regular character in the font, just a bit hard to remember and not found on keyboards -- except on greek ones, of course.
${\#}{\#}$ \mu ${\#}{\#}$, $\mu$ ìs TeX and easier to remember, together with a lot more of useful brothers and sisters.
Even more sorry to say that µ looks better when embedded in the regular font...)​

Anyway, the physicists are happiest when they see m₂ = µ m₁. Schoolteachers might prefer m₂ = 3 kg because that's what's in their solutions manual.

 

[Medgirl314]

Haha, not everyone had gotten far enough in physics to know that the quadratic formula taught in algebra is not the only quadratic equation. No need to have a panic attack. Oh, I just didn't move the numbers around enough. If you add m2 to both sides you do get m2=$\mu$Mm1 . So now we just put the numbers in? Did I really overcomplicate that much??

Thanks for the LaTex directions, I couldn't find $\mu$ with the Greek symbols and,unfortunately, I don't have time to learn the entire code.

 

[Medgirl314]

Hmm, I think I added an extra letter here. m2=μMm1

Better? m2=μm1

 

[Medgirl314]

Using this equation:m2=μm1
m2=0.25*12
m2=3

Hmm. I can't decide if this sounds reasonable. At first I thought m2 would have to be bigger than m1, but gravity is probably helping a little. Could someone check the equation/arithmetic? It almost just looks to simple.

Thanks again!

 

[Medgirl314]

Bump.

 

[haruspex]

Using this equation:m2=μm1
m2=0.25*12
m2=3

Hmm. I can't decide if this sounds reasonable. At first I thought m2 would have to be bigger than m1, but gravity is probably helping a little. Could someone check the equation/arithmetic? It almost just looks to simple.

That's the right answer. It has nothing to do with gravity "helping". As your equation shows, gravity canceled out, so as long as it is nonzero you will get the same result.
The point is that m₂ is not lifting m₁.

 

[Medgirl314]

Thank you! That makes sense. I was actually comparing it to lifting, not sliding. Oops. I couldn't lift something 4 times my bodyweight, but I could definitely make it slide on a frictionless surface.