Air Resistance: an 80

Multiple Choice

Air resistance: An 80.0-kg object is falling and experiences a drag force due to air resistance. The magnitude of this drag force depends on its speed, v, and obeys the equation F_drag = (12.0 N ∙ s/m) v + (4.00 N ∙ s²/m²) v². What is the terminal speed of this object?

A) 6.45 m/s
B) 72.2 m/s
C) 34.2 m/s
D) 12.6 m/s
E) 47.3 m/s