Ajet fighter flying at 300 m/s (just below the speed of sound) makes a turn of radius 1.85 km. (a) what is its centripetal acceleration in gs?

centripetal acceleration can be determined using the following equation;
a = v² / r
a= centripetal acceleration
v = velocity 
r = radius
substituting the values in the equation,
a = (300 m/s)*(300m/s) / (1.85 *1000) m
   = 48.64 ms-²

Velocity is the speed of an object in a certain direction so you'd need to know speed and direction