The time it takes for the bomb to hit the ground only depends on the vertical motion. We can use the equation of motion: h = 0.5gt^2, where h is the height, g is the acceleration due to gravity (approx. 9.8 m/s²), and t is the time.
Rearranging for t gives: t = sqrt(2h/g).
First, convert the height from meters to kilometers: 490m = 0.49km.
Then, plug in the values: t = sqrt(2*0.49km/9.8 m/s²) = sqrt(0.1 s²) = 0.316 s.
So, the bomb will hit the ground after approximately 0.316 seconds.