Question

A plane is flying east when it drops some supplies to a designated target below. The supplies land after falling for 10 seconds. How high above the ground was the airplane when the supplies were dropped? (Hint: d = 1/2gt2; g = -9.8 m/s2)
120 meters


490 meters


980 meters


49 meters

Answer 1

I think this is what you call a "conundrum" .

-- If there's air resistance, then the airplane can fly, but the question can't be answered with the given information.

-- If there's no air resistance, then the supplies were dropped from 490 meters above the ground, but the airplane can't fly.

Answer 2

solution:

As Given plane is flying in east direction.

It throws back some supplies to designated target.

Time taken by the supply to reach the target =10 seconds

g = Acceleration due to gravity = - 9.8 m/s²[Taken negative as object is falling Downwards]

As we have to find distance from the ground to plane which is given by d.

d = $\frac{1}{2}\times g\times t^2$

 = $\frac{1}{2}\times (9.8) \times(100) =50\times 9.8=490$ meters

Distance from the ground where supplies has to be land  to plane  =  Option B =490 meters