Science Forums: dstebbins - Viewing Profile - Science Forums

Is there an easier way to find the sum of all whole numbers between x and y (including x and y themselves) than to just sit there and painstakingly add every one up individually?

Like, for example, I know that an easier way to find the cumulative product of all whole numbers between 1 and x all multiplied together is to simply punch in the equation "x!" into a calculator, so you don't have to painstakingly multiply 1*2*3*4*5...*x. Is there a similar "shortcut" for addition?

According to this article:

http://www.cracked.c...as-enemies.html

We have a lot of misconceptions about international politics.

I remember reading this article and thinking "okay, we may not get blown up, but we'll probably all die from upcoming natural disasters. I mean, our abuse of the world's resources have made the world unstable, leading to many natural disasters like the Haiti megaquake."

But then again, these myths - the ones about foreign policy - were all quelled. Maybe the rumor about an unstable planet is similarly grounded in propoganda.

Is there any real scientific truth to it?

In terms of milliseconds, how long would it take an object in a vacuum to freefall from its starting point, to the ground a meter away, accelerating at precisely 1g?

Like, if NASA were to make a vacuum chamber, not a single millimeter above or below sea level, suck all the air out of it, and, using a mechanical hand, drop some kind of pellet to the ground that is precisely 1,000 millimeters beneath it, how many milliseconds later would it hit the ground?

I'm pretty sure that this requires a more precise definition of 1g besides simply 9.8 meters per second squared. I read that the actual acceleration of 1g is in fact 9806.65 millimeters per second squared, so this requires some very precise and delicate math.

Oh, by the way, when I said "not a millimeter above or below sea level," what I mean was, the 1,000mm-high vacuum chamber is exactly 500mm above sea level and 500mm below sea level. As much as is physically possible, the acceleration is precisely 1g. After all, your velocity is increasing at a linear rate, due to your acceleration in a vacuum, but at the same time, according to Newton's gravity equation, the acceleration that dictates the linear rate at which your velocity increases will itself increase exponentially as you get closer to the gravity source!

Yeah, I know, this is every logistics experts' wet dream! heehee!

Lots of scientists are racing to find ways to power cars without expensive fuels.

Some people suggesting having a car that runs on hydrogen, and then, funneling the water that was created back into the engine. Unfortunately, due to the law of science that says that no system can ever be 100% efficient, that wouldn't work.

However, what if cars ran on magnets? Public roads would be replaced with tracks that are made of north pole magnets. The tracks would look like metal T's protruding out of the ground, which would keep the cars (with north pole magnets on the bottom) from simply being lifted up into the air. Tracks, in this case, would have to go into each person's private garage, but at the same time, there's no more fuel to worry about!

The north pole magnets in the bottom of the car would be in the form of hundreds of poles. The poles would stick out diagonally towards the back of the car when you wanted to go forward. When you wanted to put on the breaks, half of the north pole magnets would point diagonally backwards, and half would point diagonally forwards, balancing the magnetic forces out, creating equilibrium and causing the car to remain stationary relative to the ground.

There's also some south pole magnets wrapping around the car like a belt, which would repel themselves against other south pole magnets wrapped around other cars, thus preventing a good number of collisions.

Turning, accelerating, and parking wouldn't need fuel. The re-adjusting of the north pole magnets and the direction they turn can be done completely using simple machines and muscle power!

The biggest problem, that I can see, is convincing entire cities to revamp their road systems.

Thoughts?

I you have a savings account with 1% APY and monthly compounding interest, what's the APR?

Also, what would be the APR for a 1% APY savings account whose interest compounded quarterly, bi-monthly, semi-monthly, bi-weekly, weekly, and daily?