The correct option is (c).
Explanation
Thrust is a mechanical concept referring to the total force applied perpendicular to a surface. It is a vector quantity and serves as the basis for understanding pressure.Statement 1 is Correct: Thrust is specifically defined as the force acting normally (perpendicularly) on a surface. Any force applied in a direction other than perpendicular must be resolved into components, with only the perpendicular component constituting the thrust.
Statement 2 is Incorrect: The effect of thrust is dependent on the area over which it acts. This relationship is defined by Pressure, which is the thrust per unit area ($P = \frac{\text{Thrust}}{\text{Area}}$). For the same amount of thrust, the effect (pressure) increases if the area decreases and decreases if the area increases.
Statement 3 is Correct: Since thrust is a form of force, it shares the same physical dimensions and units. The SI unit of thrust is the Newton (N).
Key Takeaway: Thrust is the total perpendicular force acting on a body, measured in Newtons. Pressure is the effect of that thrust distributed over a specific area, measured in Pascals ($N/m^2$).