How Far Should a Pilot Release a Bomb to Hit a Target?

[MorganJ]

An airplane flies horizontally with a speed of 300 m/s at an altitude of 400 m. Assume the ground is level. What horizontal distance from a target must the pilot release a bomb so as to hit the target? I know the answer is 2.7 km because it is or a review packet prior to a big test however, I do not know how my teacher got the problem.



Is it x=1/2at^2+vot?
I am confused!

 

[lewando]

To pick appropriate kinematic equations, first take an inventory of what we know about the bomb:
[let's assert that (x,y,t) = (0,0,0) = position and moment in xy-plane when bomb is released]
vx(0) = 300 m/s
vx(t) = 300 m/s
vy(0) = 0 m/s
T = time from bomb release to target impact
y(T) = -400 m
ay = -9.8 m/s²
ax = 0 m/s²

What are we looking for:
T
x(T)

Is this clear so far?

 

[MorganJ]

Yes, this is clear. So we have do we do x=1/2at^2+vot?

 

[lewando]

Your x-axis equation boils down to x(T) = vx(0)T because ax is zero. Need to find T. Can you apply the y-axis version of your equation and see where it takes you?