When the drone is in flight, which of the following sequences represents the typical energy transfers occurring in its power system?

• A electrical $\to$ chemical $\to$ kinetic
• B chemical $\to$ electrical $\to$ kinetic
• C chemical $\to$ kinetic $\to$ electrical
• D kinetic $\to$ electrical $\to$ chemical

During a portion of its flight, the drone travels at a constant horizontal velocity of 24 m/s. $\backslash nState$ the equation linking kinetic energy ($KE$), mass ($m$), and velocity ($v$).

Calculate the kinetic energy of the drone when traveling at this speed.

The drone takeoff involves climbing vertically to a cruising altitude of 800 m. $\backslash nState$ the equation linking gravitational potential energy ($GPE$), mass ($m$), gravitational field strength ($g$), and height ($h$).

Calculate the gravitational potential energy gained by the drone when it reaches this altitude.

The fuel cell stack provides a maximum total output power of 15 kW. To ensure safe takeoffs, the drone also carries a reserve rechargeable battery. Show, by calculation, that the drone requires this battery to climb to 800 m in $3.5minutes$.

The fuel cells are connected in series in a stack. The voltage across each individual fuel cell is 0.7 V, and the maximum current through each cell is 25 A. Show that there must be more than 850 fuel cells in the stack to achieve the maximum power output of 15 kW.