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threewingedfury · 02-13-2006, 08:10 PM

In Figure 13-34, a square of edge length 19.0 cm is formed by four spheres of masses m1= 6.00g, m2= 4.00 g, m3= 1.00 g, and m4= 6.00 g. In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5= 2.50 g?

All of the masses are the same distance from m5, and the distance is d= 13.44 cm 0.1344 m.

How exactly can come up with whats in the bold? This is an example of a problem I have to do, and I know how to work it, I just can't figure out how they found this distance. Is there a certain equation for this?

Thanks in advance

kutulu · 02-14-2006, 08:21 AM

scratch that, I didn't see that you knew how to solve it.

So you don't need to know how to solve it? I would have just assumed that they made the distance up. It's just a homework problem.

rlbond86 · 02-14-2006, 08:50 AM

They get the distance by drawing a line from m5 to each of the masses.
The length of the side of the square is 19, so the length of the diagonal is 19*sqrt(2), so half the diagonal is 9.5*sqrt(2) = 13.44

threewingedfury · 02-14-2006, 11:10 AM

thank you!
kutulu - the problem I had had different masses and length and I was given the way to work it out, I just couldnt figure out how they found the distance, so I couldn't do the rest of the work past the distance

I just added in part of the answer..

02-13-2006, 08:10 PM	#1 (permalink)
threewingedfury Upright	physics problem In Figure 13-34, a square of edge length 19.0 cm is formed by four spheres of masses m1= 6.00g, m2= 4.00 g, m3= 1.00 g, and m4= 6.00 g. In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5= 2.50 g? All of the masses are the same distance from m5, and the distance is d= 13.44 cm 0.1344 m. How exactly can come up with whats in the bold? This is an example of a problem I have to do, and I know how to work it, I just can't figure out how they found this distance. Is there a certain equation for this? Thanks in advance Last edited by threewingedfury; 02-13-2006 at 09:36 PM..

02-14-2006, 08:21 AM	#2 (permalink)
kutulu Junkie	scratch that, I didn't see that you knew how to solve it. So you don't need to know how to solve it? I would have just assumed that they made the distance up. It's just a homework problem. Last edited by kutulu; 02-14-2006 at 08:24 AM..

02-14-2006, 08:50 AM	#3 (permalink)
rlbond86 Insane	They get the distance by drawing a line from m5 to each of the masses. The length of the side of the square is 19, so the length of the diagonal is 19sqrt(2), so half the diagonal is 9.5sqrt(2) = 13.44

02-14-2006, 11:10 AM	#4 (permalink)
threewingedfury Upright	thank you! kutulu - the problem I had had different masses and length and I was given the way to work it out, I just couldnt figure out how they found the distance, so I couldn't do the rest of the work past the distance I just added in part of the answer..