no it is because the strength of the motor is based on the density of the object that it is attached to. gold weighs more therefore it is stronger even though the motor strength is the same
Ok so when you start the scene the rocket is already going. If you zoom out and look way above the rocket there is an orange plane flying. hold the "a" key while the plane is above the laser that is to the left of the rocket and the laser will turn on and target the airplane. Then, the rocket will follow the plain and hit it.
btw inertia multiplier only affects an objects rotational inertia. the higher the number, the more energy is needed to spin the object but it retains the inertia better
for example, if you had an object with 5 inertia mult and another with 1, then the object with 1 inertia multiplier will spin faster but will slow the spinning down easier if it hits something