$\pi r^{2} x \rho_{w} g  = - m \frac{d^{2}x}{dt^{2}} $

{{{id=1|
# but for water rho_w = 1

#given that r = 30 * 10^(-2) m

Buoyant_force = ( ((9.8* (30 * 10^-2)**2))/ 3.1451 )* 9.8
print Buoyant_force #(in newton)
///
2.74827509459159

{{{id=4|

/// }}}}}}