Answer:
E) 800 km/h
Explanation:
The computation of the average vector velocity module of the plane, at that time is shown below:
The displacement vector is
d^2 = d1^2 + d2^2
where,
d1 = northeast displacement
d2 = southeast displacement
Now
d^2 = (120)^2 + (160)^2
= 14400 + 2560
= 40000
= √40000
d = 200 km
Now the average velocity is
V = ΔS ÷ Δt
= 200 ÷ 1 ÷ 4
= 200 × 4
= 800 km/h