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Gold3nlily
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Homework Statement
Two dimensions. In Figure 13-34, three point particles are fixed in place in an xy plane. Particle A has mass mA = 7 g, particle B has mass 2.00mA, and particle C has mass 3.00mA. A fourth particle D, with mass 4.00mA, is to be placed near the other three particles. What (a) x coordinate and (b) y coordinate should particle D be placed so that the net gravitational force on particle A from particles B, C, and D is zero (d = 24 cm)?
Figure:
http://edugen.wiley.com/edugen/courses/crs4957/art/qb/qu/c13/qu_1.14.gif
Homework Equations
F = (GMm)/r2
Fab + Fac + Fad = 0
split into vector components?
G = 6.67e-11
The Attempt at a Solution
X component:
(no Fab b/c that's all in y component)
Fac + Fad,x = 0
Fac = (GMamc)/rac2
Fac = [(0.007)(.021)(6.67e-11)]/ (.36)^2 = 7.57e-14
Fad,x = - 7.57e-14
So use force to solve for distance (x component of Fad): rad
Fad = (GMamd)/(rad)2
rad2 = [(0.007)(.028)(6.67e-11)]/ - 7.57e-14
rad = - 0.457m
Before I type up the y component... What should I do differently?