A drone is initially at rest at the origin point, coordinates (0,1), and begins to move across the xy-plane. It accelerates at a constant rate, described by the vector $\vec{a}=(5.0\hat{i}+7.0\hat{j})\mathrm{\ m}/\mathrm{s}^2$. What is the drone's speed as a function of time?

• A. $3.5t^2\mathrm{\ m}/\mathrm{s}$
• B. $12t^2\mathrm{\ m}/\mathrm{s}$
• C. $8.6t\mathrm{~m}/\mathrm{s}$
• D. $74t\mathrm{\ m}/\mathrm{s}$

Answer: (C)