Constant Acceleration

[Graeme H]

(To be picky, it is change of displacement over change of time …)

[Stoatstail50]

Overthinking...my aopolgies.

[James9118]

I think this thread is highlighting the difference between pure mathematics and what's practical in real life. When terms like 'constant acceleration' are used the pure mathematician sees a step function i.e. at time zero the acceleration is increased from zero to whatever the constant rate is. When you subsequently differentiate a step function you end up with an infinity solution, i.e. a massive jerk (where 'jerk' is used to describe the differential of acceleration, or the third differential of position if you prefer). As far as I'm aware, the human body cannot just jump to an acceleration rate (nor can any machines that I know of) therefore constant acceleration at times near zero simply cannot happen.

Graeme - your example reminds me of a question I used to ask at interviews - if a plane travels to it's destination at 400mph and comes back at 600mph, what is it's average speed for the round trip. The answer being 480mph - amazing how many very well educated people struggled with that one.

James

[Graeme H]

… and the average velocity is zero. (But I guess that was the second most common answer.)

[James9118]

… and the average velocity is zero. (But I guess that was the second most common answer.)

I would prefer that answer over someone who just blurted out 500 In fact, I preferred a 'I don't know' over someone saying 500

[VGB]

if a plane travels to it's destination at 400mph and comes back at 600mph, what is it's average speed for the round trip. The answer being 480mph - amazing how many very well educated people struggled with that one.

The right answer is 417 kts, planes don't do mph And you would have to specify if that is TAS, CAS, EAS or Groundspeed

[Graeme H]

You get the job Vince. No time to retire for you!

[Mangrove Cuckoo]

So...

if I had to get out a pencil and paper to figure that out... does that prove or disprove I'm well educated?

[Stoatstail50]

Me too...I'm going back into my cage.

[VGB]

So...

if I had to get out a pencil and paper to figure that out... does that prove or disprove I'm well educated?

That depends entirely on what you do with the pencil