The stupid ones will always be stupid and the smart ones will always be smart no matter what I do.
Yeah, about that... I'm a physics teacher and in my experience there is certainly a point at which the lack of innate ability means that a student would be better employed trying to learn something else. Sure, we try to teach all of our students as much as we can, but if after a year or so of intensive teaching, extra support classes, peer supported group work &c. a student still struggles to grasp the basics of electrical circuit analysis or the process of resolving vectors into orthogonal components then it's time to run up the white flag and try something else. The myth that anyone can be successful at anything has lead many young people to waste a great deal of time and effort trying to master ideas that are frankly beyond them. What I think we forget sometimes is just how intellectually / academically weak it is possible for some people to be. Life is short and youth even shorter. Surely it is better to spend your time productively rather than on impossible and ultimately fruitless pursuits?
Wow, a lesson in design tradeoffs. You can't have a large comfortable, safe car with several air bags, an enormous crumple zone with decent acceleration that gets 40 MPG.
Without looking too hard, I've found a car that gets 60MPG (Imperial - so about 50MPG US gallons) and will get you from 0 to 60 in 9 seconds witha top speed of around 130 mph. Seems like a long list of safety kit too. http://www.whatcar.com/car-reviews/alfa-romeo/giulietta-hatchback/2-0-jtdm-140-lusso-5dr/specifications/62201
Force needed to accelerate 2.2lbs of cookies = 1 Fig-newton to 1 meter per second