To solve this problem, we can use the equations of motion for projectile motion. Since the dart is thrown horizontally, we know that there is no vertical velocity and that the only acceleration acting on the dart is gravity, which is 9.8 m/s^2 downward.
The vertical motion of the dart can be described by the equation:
y = y0 + v0t + 0.5at^2
where y is the vertical position of the dart, y0 is the initial vertical position (which is 0 in this case), v0 is the initial vertical velocity (which is also 0), t is the time of flight, and a is the acceleration due to gravity.
To find the time of flight, we can use the horizontal motion of the dart, which is described by the equation:
x = x0 + v0t + 0.5at^2
where x is the horizontal position of the dart, x0 is the initial horizontal position (which is 0), v0 is the initial horizontal velocity (which is 12 m/s), and t is the time of flight.
We know that the horizontal position of the dart is 2.7 m, so we can substitute that into the equation and solve for t:
2.7 = 0 + 12t
t = 2.7/12 = 0.225 seconds
We can then substitute t and a into the vertical motion equation to find the vertical position of the dart:
y = 0 + 0 + 0.5(9.8)(0.225^2)
y = -0.061 m
So the dart hits 0.061 m below the intended target.