That depends upon the direction of its initial velocity. You must have left some words and a number out of your question.
Whatever it is, add the two vectors.
if a plane is flying 235 km/h and encounters west wind at 80 km/hr. What's its new velocity?
2 answers
The original velocity is not known because the flight direction has not been given.
For example, if it was heading west, the velocity is simply reduced by 80 k/hr to become 153 k/h (ground speed) heading west.
For example, if it was heading west, the velocity is simply reduced by 80 k/hr to become 153 k/h (ground speed) heading west.