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\frac{\mathrm{d} \mathrm{V}}{\mathrm{dt}}=3 \mathrm{~s}^{2} \frac{\mathrm{d} \mathrm{s}}{\mathrm{dt}}-4 \pi \mathrm{r}^{2} \frac{\mathrm{dr}}{\mathrm{dt}}=3(12 \, \mathrm{ft})^{2}