Question

please help me in this question

Answer 1

Let unit vector along north be j and along east by i

Initial velocity of ship = (40 kmph) j
Final velocity of ship = (40 kmph) i

Change in velocity = Final velocity - Initial velocity
= 40 i - 40 j
= 40 i + 40 (-j)

Magnitude of change in velocity
= √(40² + 40²)
= 40√2 kmph

Direction:
i is along east and -j is along south.
Both have same magnitudes
So, direction of change in velocity is South East

In simple, for same magnitudes
i + j = North East
i - j = South East
j - i = North West
-i - j = South West