Cruise and Brake

Hovering at $19.6\ \mathrm{m}$, the $2\ \mathrm{kg}$ drone cruises to the right, toward the customer, at $20\ \mathrm{m/s}$. Then its rotors keep holding it up while they brake it with a horizontal $8\ \mathrm{N}$, until it flies at $12\ \mathrm{m/s}$. Taking forward as positive, find the braking distance $d$.