Conservation of mass in action.
Rainwater flows in and gets concentrated into the river channel - more material squashed into a tighter cross-sectional area has only one escape valve: flow faster and faster.
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Once a student understands physics, they often marvel at how easy it is (regardless of the time, energy, or suffering it took them to get to this point).
"Impulse is change in momentum"
Actually, impulse is force applied over a time interval. The connection with momentum is a nontrivial consequence of this, not a definition in-and-of itself.
Otherwise, why would we even bother giving it a name if it was just p_f - p_i?
3) Write down the list of equations you will potentially need to solve this problem.
4) Begin solving the problem.
This process maximizes the chances of being correct every time. If you struggle with physics, try this routine.
Every high school and college physics problem should be tackled in this manner:
1) Rewrite the problem statement using symbols, variables, and such, making sure to express all given quantities (knowns) and the quantity one is searching for (unknowns).
2) Draw a picture.
If you are taking AP Physics I, the most important single skill to practice is matching up a physics problem with the equations you'll need to solve it. Just 'what variables do they give me, what variable am I looking for, what equations match that?'
@palan57@MichaelPetrilli Honestly, time. When a professor writes a textbook, they go on sabbatical. Creating good course materials while teaching would be an enormous demand on a person's time. Both teaching and writing good teaching materials are too intensive to do either halfway.
The 2% target incentivizes people to invest wealth instead of hoarding it. This is essentially the principle that the world economy is organized around. In particular, even if you don't think it's worth it, it's baked into every financial instution. Meaning, actual deflation would cause massive problems with every single financial institution at once.
@GrantSlatton I think they deliberately chose to ignore any text with a number in it (maybe with the thinking it would be a url or a proper noun or something that shouldn't be corrected). So, just don't do that and I think you'd be well on your way.
@JoanneLeeJacobs It's funny how counter-intuitive it all is. I mean, if you had to guess ahead of time, you would assume that leveled-reading groups would work great.
What I would want is some kind of loose framework for a sort of explicit instruction self-study for arbitrary topics. You would never be able to do it properly, but surely it's possible to beat pure unguided reading.
In the 1960's, progressive reformers started pushing whole-word or whole-language constructivist methods to teach children to read. By the 90's, they had acquired enough cultural and political caché to push these methods nationwide.
However, falling test scores have recently prompted a sudden return to phonics-based methods. Whole-word advocates decry this as reactionary, conservative, right-wing nonsense. They talk about how phonics has ties to religious groups and homeschoolers.
When confronted with the success of phonics-based methods, they assert that the system has always been phonics-based to a greater or lesser extent, and that changes in test scores, drastic as they may be, are due to a complex tapestry of issues.
The country in question is Brazil.