Question

please tell me why thrust is vector quantity while pressure (thrust per unit area) is scalar quantity

Answer 1

Scalars are quantities that are fully described by a magnitude 

Vectors are quantities that are fully described by both a magnitude and a direction.



Thrust has both magnitude and direction so it is called vector quantity. 
Pressure has magnitude only thats why it is called scalar quantity.

Answer 2

because thrust has both magnitude and direction[vector quantity].but pressure has only magnitude.[scalar quantity]