Newton
Explanation
Thrust is defined as the force acting perpendicularly on the surface of an object. Since thrust is a specific type of force, it is a vector quantity and is measured using the same standard units as force.
Option Analysis
- Pascal is incorrect: Pascal ($Pa$) is the SI unit of Pressure, which is defined as thrust per unit area ($1 Pa = 1 N/m^2$).
- Newton is correct: Newton ($N$) is the SI unit of Force. Since thrust is the total force acting perpendicular to a surface, its SI unit is the Newton.
- Joule is incorrect: Joule ($J$) is the SI unit of Work or Energy.
- Watt is incorrect: Watt ($W$) is the SI unit of Power, defined as the rate of doing work.
Key Takeaway
Thrust is a force and is measured in Newtons ($N$). Pressure is the effect of thrust distributed over an area and is measured in Pascals ($Pa$).