Question

The thrust developed by a rocket-motor is given by $F=mv+A\left(p_1-p_2\right)$, where $m$ is the mass of the gas ejected per unit time, $v$ is velocity of the gas, $A$ is area of cross-section of the nozzle, $p_1,p_2$ are the pressures of the exhaust gas and surrounding atmosphere. The formula is dimensionally

• A. correct
• B. wrong
• C. sometimes wrong, sometimes correct
• D. data is not adequate

Answer 1

Answer: (A)

Each of the three terms in the given equation has the dimensional formula of force.