Answer:
81 km/h W52°S
Step-by-step explanation:
The bird's initial velocity is 25 km/h, 45° east of north. The components of the velocity are:
aₓ = 25 sin 45
aᵧ = 25 cos 45
The bird's final velocity is 56 km/h, 35° west of south. The components of the velocity are:
bₓ = -56 sin 35
bᵧ = -56 cos 35
The change in velocity is the final velocity minus the initial velocity.
cₓ = bₓ − aₓ
cₓ = -56 sin 35 − 25 sin 45
cₓ ≈ -49.8
cᵧ = bᵧ − aᵧ
cᵧ = -56 cos 35 − 25 cos 45
cᵧ ≈ -63.6
The magnitude is found using Pythagorean theorem:
c² = cₓ² + cᵧ²
c² = (-49.8)² + (-63.6)²
c ≈ 81 km/h
The direction is found using trigonometry:
θ = atan(cᵧ / cₓ)
θ = atan(-63.6 / -49.8)
θ ≈ 52°
The change in velocity is 81 km/h W52°S.