The diagram shows the only four forces acting on a model aircraft of mass 2.0 kg whilst flying. Which line in the table states the horizontal and vertical accelerations of the aircraft at this instant?

Answer:

15) A

∑F (horizontal direction) = 50-40 = 10 N to the right
We know the mass = 2kg
Force = mass x acceleration

Acceleration = force/mass = 10/2 = 5.0m/s2 to the right 

∑F (vertical direction) = 25N-20N = 5N upwards
Acceleration = force/mass = 5/2 = 2.5 m/s2 upwards

Hence, the answer is A