an aircraft executes a horizontal loop of radius 1 km with a steady speed of 900km/h,compare the

Here, r = 1 km = 1000 m

          v = 900 km/hr = 250 m/s

Now the centripetal acceleration ,

a_c = v² / r = (250)² / 1000  =  62.5 m/s²

The centrip[etal acceleration relative to acceleration due to gravity

a_c  / g = 62.5 / 9.8 = 6.38