Remember your HS Physics?
Me neither. Didn't take it. But have come across something called 'kinetic energy' (energy of movement) that is quantified by the formula K.E. = 1/2 Mass times Velocity Squared. The question often ...
Forum Discussion
DrewE wrote:GordonThree wrote:
KE unit is joules right? I'm fuzzy on that part of highschool physics too, just how much is a joule ... is it the amount of energy that'll raise one g of water one degree c or something like that?
That would be a calorie (with a small c), one thousandth of a Calorie (with a big C) or kilocalorie that is used for foods. A joule is a kilogram meter squared per second squared (which clears everything up, right?), or equivalently a watt-second. It's a bit less than a quarter of a calorie (with a small c).
Naturally, the nature of the relationship between kinetic energy and velocity is the same regardless of what units one uses. In terms of surviving a crash, arguably more important than the total energy dissipated is the rate of deceleration, which incidentally has a lot to do with how large crush structures on vehicles need to be in order to be effective.
Yep, he got it right.
If the velocity is in meters/sec and the mass is in kilograms, the energy is in joules. A joule is not very much energy, but when you start talking about 10,000 kg traveling at 60 mph (26 m/sec), it turns into a lot of energy.
So..... slow down.
