A solid sphere of radius, $r,$ and made of material with density, $\rho_{s},$ is moving through the atmosphere (constant pressure, $p$ ) with a velocity, $v$. The net force ONLY due to atmospheric pressure $\left(F_{p}\right)$ acting on the sphere at any time, $t$, is

(A) $\pi r^{2} p$

(B) $4 \pi r^{2} p$

(C) $\frac{4}{3} \pi r^{3} \rho_{s} \frac{d v}{d t}$

(D) zero

A solid sphere of radius, $r,$ and made of material with density, $\rho_{s},$ is moving through the atmosphere (constant pressure, $p$ ) with a velocity, $v$. The net force ONLY due to atmospheric pressure $\left(F_{p}\right)$ acting on the sphere at any time, $t$, is

(A) $\pi r^{2} p$

(B) $4 \pi r^{2} p$

(C) $\frac{4}{3} \pi r^{3} \rho_{s} \frac{d v}{d t}$

(D) zero

127