Motion Problem Using F=Ma and s=ut+1/2xt^2

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Discussion Overview

The discussion revolves around a physics problem involving the motion of a package dropped from an aircraft during a training supply drop. Participants explore the application of the equations of motion, specifically F=ma and s=ut+1/2at^2, to determine the horizontal distance from the target for the package release and the impact force upon landing. The context includes both theoretical and practical aspects of motion in a low-level aviation scenario.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • The original poster (OP) describes a scenario involving a 10kg package dropped from an aircraft at a speed of 150 m/s and an altitude of 200m, with specified accelerations in both vertical and horizontal directions.
  • Some participants point out that the equation provided by the OP, s=ut+1/2xt^2, is incorrect and should be s=ut+1/2at^2, clarifying that 'a' represents acceleration.
  • One participant suggests that the force equation F=ma is unnecessary for solving the problem since the OP is not asked about the force, focusing instead on the motion equations.
  • Another participant explains how to find the time of fall using the vertical motion equation and then apply that time to calculate the horizontal distance using the horizontal motion equation.
  • There is a mention of the OP's inquiry about the impact force, which some participants acknowledge as part of the problem but do not elaborate on how to calculate it.

Areas of Agreement / Disagreement

Participants generally agree on the need to use the correct motion equations, but there is no consensus on the necessity of the force equation or how to approach the calculation of the impact force. The discussion remains unresolved regarding the exact calculations and the impact force.

Contextual Notes

Some limitations include the OP's initial misunderstanding of the equations, the need for clarification on the correct form of the motion equations, and the lack of specific values for time and distance calculations. The discussion does not resolve how to calculate the impact force based on the given information.

jakan
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Firstly, appologies if this is in the wrong place or wrote wrong, total noobie here.

Ive been given some examples of math questions based on aviation, unfortunately this one didn't come with the correct answer or any example working and it seems a little more tricky than the others so I am struggling with where to start and knowing if I am getting decent answers. (Its for an oral examination with a maths element, don't worry the scenaria and numbers I get will be completely unknown to me):

A aircraft is conducting a low-level training supply drop run with the intention of dropping a 10kg package on a target location. The aircraft is at a constant speed of 150ms^-1 at an altitute of 200m.

At package release, the package is subject to a constant acceleration in a downward vertical direction of 4ms^-2 and in the horizontal direction of -3ms^-2 (ie against direction of travel).

At what horizontal distance from target should the package be released and what will the impact force be?

Equations given are F=ma and s=ut+1/2xt^2

Any help or pointing in right direction will be appreciated, other examples used other motion equations I had no issue with.
 
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jakan said:
Firstly, appologies if this is in the wrong place or wrote wrong, total noobie here.

Ive been given some examples of math questions based on aviation, unfortunately this one didn't come with the correct answer or any example working and it seems a little more tricky than the others so I am struggling with where to start and knowing if I am getting decent answers. (Its for an oral examination with a maths element, don't worry the scenaria and numbers I get will be completely unknown to me):

A aircraft is conducting a low-level training supply drop run with the intention of dropping a 10kg package on a target location. The aircraft is at a constant speed of 150ms^-1 at an altitute of 200m.

At package release, the package is subject to a constant acceleration in a downward vertical direction of 4ms^-2 and in the horizontal direction of -3ms^-2 (ie against direction of travel).

At what horizontal distance from target should the package be released and what will the impact force be?

Equations given are F=ma and s=ut+1/2xt^2

Any help or pointing in right direction will be appreciated, other examples used other motion equations I had no issue with.

Your equation s=ut+1/2xt^2 does not seem to be correct it is usually written s=ut+1/2at^2 where a is the acceleration.

you find t by looking at the motion vertically and then s using the value of t you have found in the horizontal equation
 
You don't really need "F= ma" since you are not given or asked about the force. You are given the vertical and horizontal accelerations so you need s= ut+ (1/2)at^2. The package has a downward acceleration of 4 m/s^2 and must fall 200 m. u is the initial speed but there was no initial downward speed so u= 0. So for the vertical motion (1/2)(4)t^2= 2t^2= 200. Solve that for t. (Notice that the acceleration is not negative because I am taking "downward" to be positive.)

You are told that the horizontal acceleration is -3 m/s^2. The initial horizontal speed is 150 m/s so the horizontal distance is given by d= 150t- 3t^2. Use the t determined above to find the distance the package will move horizontally while falling.
 
HallsofIvy said:
You don't really need "F= ma" since you are not given or asked about the force. You are given the vertical and horizontal accelerations so you need s= ut+ (1/2)at^2. The package has a downward acceleration of 4 m/s^2 and must fall 200 m. u is the initial speed but there was no initial downward speed so u= 0. So for the vertical motion (1/2)(4)t^2= 2t^2= 200. Solve that for t. (Notice that the acceleration is not negative because I am taking "downward" to be positive.)

You are told that the horizontal acceleration is -3 m/s^2. The initial horizontal speed is 150 m/s so the horizontal distance is given by d= 150t- 3t^2. Use the t determined above to find the distance the package will move horizontally while falling.

Well, to be fair, the OP did ask about the impact force in the latter part of their sentence.
 
Ah, thanks.
 

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