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An aeroplane flying with constant speed releases a bomb. Neglecting air resistance, where will the bomb land?

  1. Below the aeroplane

  2. Behind the aeroplane

  3. In front of the aeroplane

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closed as off-topic by kleingordon, John Rennie, Bernhard, Qmechanic Nov 7 '14 at 13:30

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Please state air resistance clearly in the problem.

$v_{plane,x-direction}=v_{bomb,x-direction}$ before the release of the bomb. $v_{plane,x-direction}>v_{bomb,x-direction}$ after the release of the bomb, due to the air resistance.

Therefore, after some period $t$, when the bomb hit the ground, it will be left behind the plane in the $x$-direction.

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  • $\begingroup$ Thanx. BUT have you neglected or considered the horizontal air?@physics.stackexchange.com/users/40930/guo-qianyi $\endgroup$ – Shobik Gupta Nov 7 '14 at 10:26
  • $\begingroup$ $v_{bomb}$ becomes smaller than $v_{plane}$ due to air resistance in $x$-direction. Air resistance in $y$-direction has nothing to do with its landing location, but only influences the landing time $t$. $\endgroup$ – Qianyi Guo Nov 7 '14 at 10:28
  • $\begingroup$ oh now i got my mistake i was not considering the landing time in y-direction $\endgroup$ – Shobik Gupta Nov 7 '14 at 10:31
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If you are neglecting air resistance and the velocity of the plane remains constant after the bomb is released, then the bomb's horizontal velocity remains the same and it must land directly under where the plane has moved to when it impacts the ground.

If you include air resistance then the horizontal velocity of the bomb is reduced compared with that of the plane and the bomb must land at some distance behind the plane.

Air resistance is generally treated as a force proportional to the square of the velocity directly opposite in direction to the total velocity of the object ( vector sum of is horizontal velocity and the vertical velocity resulting from the effects of gravity on the bomb) and the constant of proportionality is dependent on the cross-sectional area normal to that velocity.

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  • $\begingroup$ As @Omen said, we're trying not to be a homework completion service. $\endgroup$ – Mike Dunlavey Nov 7 '14 at 13:05
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Try to think about the problem a bit.

  1. As stated in the problem you do not consider air resistance.

  2. You have gravity which only act downwards.

  3. If there is no air resistance, will anything decrease the velocity of the falling bomb (either parallell to the plane or vertically toward the ground)?

  4. If not, what does that say about the velocity in the direction along the plane? How does that relate to the constant velocity of the aircraft?

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