Question

What is the formula to find specific impulse?

(a) Jsp=m/v

(b) Jsp= J/m

(c) Jsp=T/m

(d) Jsp=J/q

This question was addressed to me during a job interview.

The above asked question is from Impulse Momentum Equation topic in division Fluid Dynamics of Fluid Mechanics

Answer 1

The correct choice is (b) Jsp= J/m

Easiest explanation: Specific impulse is defined as impulse per weight. It can also be defined as thrust per weight of a flow rate. It is equal to the exhaust velocity divided by acceleration due to gravity. (SI Unit: m/s)