$9.$ Which method is preferred for high precision balancing of high$-$speed rotors?

$-$ A$)$ Static balancing on knife edges

$-$ B$)$ Dynamic balancing using laser sensors

$-$ C$)$ Balancing by trial and error with weights

$-$ D$)$ Manual adjustment of rotor vanes

$10.$ How does the firing order in a multi$-$cylinder engine affect the engine's operational characteristics?

$-$ A$)$ It primarily affects the timing of valve openings.

$-$ B$)$ It influences the distribution of thermal loads.

$-$ C$)$ It alters the pattern of wear on the cylinder walls.

$-$ D$)$ It helps achieve a smoother operation by balancing inherent engine vibrations.