Using Kinematic equations to describe a falling object

[4.19mile]

Homework Statement

For this project, we had to build a vehicle that would hold an egg, and drop it a distance of about 40 feet, and making sure the egg wouldn't break. There are various parts to the report part of this project, and I had a question about the first part. Basically, one part asked:

Controlling Vehicle Speed: Kinematics
Use kinematics equations to analyze the vehicle as it falls and explain how you kept the vehicle from striking the ground at an excessive speed.

Homework Equations

All the kinematic equations, so like:

vf^2 = v0^2 + 2ax
vf = v0 + at
x = v0^2 + 1/2at^2
x = vf^2 - 1/2at^2

The Attempt at a Solution

So this is what I put for the first equation, vf^2 = v0^2 + 2ax:

One equation to use is vf2 = vo2 + 2ax. For this, x is a value that is constant, basically the distance of about 40 feet, the height at which the vehicle is dropped. v0 is equal to 0, as this was the initial velocity. Therefore, to make vf, the final velocity smaller, the acceleration must be smaller. By putting a "circular disk" around the vehicle, this created air resistance, and lowered the acceleration, thereby lowering the final velocity and impacting the ground at a lower speed.

What do you think of this, is it good enough? Also, how can I implement the equations:

vf = v0 + at
x = v0^2 + 1/2at^2
x = vf^2 - 1/2at^2

into this as well, to make it tie in with the vehicle and all? This is graded fairly hard, so I am looking for some good opinions. Would really appreciate the help, thanks :)!

 

[haruspex]

What do you think of this

A small complication is that the kinematics equations you quote are for constant acceleration, but with the added parachute it is not. That does not invalidate your argument, but should be mentioned. It would also be possible to add a bit of justification.

how can I implement the equations:

It is unclear what is wanted by way of analysis. The other equations involve time. Do we care, or do we know, how long it took? I would not interpret it as implying that you have to make use of more than one kinematic equation.