Answer
$10.14\;N$
Work Step by Step
The magnitude of the upward buoyant force on the sphere exerted by the seawater is
$F_b=\rho gV$
or, $F_b=\rho g(\frac{4\pi r^3}{3})$
Substituting the given values
$F_b=1025\times9.81\times(\frac{4\times\pi \times 0.0622^3}{3})\;N$
or, $\boxed{F_b=10.14\;N}$
