Brass Ball

One end of a wire is attached to a ceiling, and a solid brass ball is tied to the lower end. The tension in?

the wire is 200 N. What is the radius of the brass ball?

First off, the wire's weight (in Newtons) needs many more facts added to it to help determine anything about the ball. Second, if the ball you're talking about is 200 N then - Force or weight (in Newton) = mass (in kg) x gravitational acceleration (in m/s2). 200 N = X * 9.8 m/s/s. This equals a mass of 20.408163 kg(I'm assuming this is on Earth) Assuming average density of 8.5 gm/cm3 for the brass sphere, then 20408.163 grams (mass) = 4/3 (3.14159 pi) r^3 (volume)* 8.5 gm/cm^3 (density). Then
2400.9604cm^3 (mass/density) = V then 2400.9604/ (4/3 pi) = r^3 then 573.18756 cm3 = r3

Take the cube root and you end up with
R = 8.306771 cm (This is all rounded off and I'm assuming a lot here since you didn't give me much to go on.)

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