February 15th, 998
A tiny form twists back and forth, weaving between the apple trees and occasional stump. The click clack of tiny wheels running over the dirt path, an orange blur passing under a sea of green. Rainbow Dash watches from high above, a slight frown crossing the cyan muzzle, clutching a superfluous stopwatch in one hoof and a clipboard in the other. A pencil sticks out from one ear, barely holding in place as she flaps up and down. She gives a decidedly unnecessary glance to the stopwatch, purely to double check of course, before writing down the final lap time for the filly.
Rainbow grins, taking the pencil, holding it away from her body. She takes a deep breath, slowly letting it out, then taking a sharp inhale while she drops the pencil. The cyan pencil, a yellow lightning bolt down one side with an orange and yellow tassel off the eraser, flutters through the air, the point aimed down and spiraling as the wind buffets it. In twenty seconds the pencil will smash into the ground, probably blunting the sharpened tip and getting a bit of dirt on the tassel.
Rainbow flies off to the side, a wide arc making an almost perfect circle, a rainbow contrail coming behind her. One eye follows the tassel, the other tracking her distance from the ground, making sure her acceleration perfectly counters gravity while maintaining a smooth curve. She grins, her filly watching the tassel fall through the air.
One hoof stretches out, the pencil seemingly barely out of reach before she tries to put on an extra burst of speed. Rainbow grits her teeth, her muscles straining as her wings beat against the air; the pencil reached its terminal velocity long ago, but the pegasus can still push herself a little more.
Her hoof reaches down, the pencil inches from the ground before her hoof grabs it, the pencil shattering from the blunt force of a hoof hitting it at two hundred miles per hour. Rainbow slows down, staring at the remains of the pencil in what might be construed by some less awesome pony as disbelief before she stomps a hoof in frustration. That's the third pencil this week! There must be something wrong with the pencils Doug uses to stock his office.
Scootaloo rides over, the filly breathing heavily as she dumps her brown scooter to the ground. She watches curiously as pieces of lead and wood flit from Rainbow's hoof, blowing away in the wind. The two pegasi watch in silence before Scootaloo remarks, "So, that was really cool, right up until the end."
"Yeah, I've gotten just about all my flight back. Still need to work a little on acceleration, I had to put more in at the end than I would have liked. And then, since I was devoting myself to speed I couldn't make the... um... momentum manipulation and inertial dampeners work right." Rainbow sighs, looking back at her wings, awkwardly rubbing her hoof against her mane, "I'll be really happy once I get my full magic back. A midair rescue would be pretty terrible if you just bisected the pony instead of saving them."
Scootaloo rubs her mane, "Yeah, that, um, that would be bad. So, what's momentum?"
Rainbow cocks an eye at Scootaloo, "You don't know what momentum is?" At the filly's sigh and head shake Rainbow grunts, "What do they teach you in school?"
"Life cycle stuff. Like how water rains down on the ground and helps the crops grow. How to figure out the right amount, and what happens to the water once it lands, like why rivers are there."
Rainbow deadpans, "So, farming."
"Yeah. Farming." Scootaloo kicks at the dirt, her tiny wings briefly fluttering before resting against her sides.
Rainbow grumbles to herself as she looks around the apple orchard the two are practicing in, eventually sighing and saying, "Well, not gonna bash farming, not where Applejack might hear me, but we gotta get you learning about the important stuff. So, momentum. Momentum. Let's see here." Rainbow taps a hoof against her chin, then her head, vainly trying to jog her memory. "Momentum. So, I know it has to do with pushing things around. And speed."
Scootaloo looks at Rainbow with a smile, slowly turning to a frown moving as Rainbow lands and starts drawing in the dirt. Scootaloo walks over, looking at the rough picture of a pegasus, an arrow pointing in one direction. Then comes the Wonderbolts with Rainbow's cutie mark leading the formation, lines waving away from each of them to show they are going really really fast. Scootaloo glances up; Rainbow notices, giving a sheepish grin and swiping at the dirt with a hoof. Scootaloo grunts, "So, you were talking about momentum."
"Oh yeah! Momentum. Like, speed. And weight. I think?" Rainbow huffs, "I can't explain this stuff, I just know it! Like, if I'm trying to catch this pencil," she holds up the tassel, all that remains of the pencil she 'caught', "I need to know how much to push it in order to avoid shattering it."
Scootaloo stares at the tassel, "Like you just did."
Rainbow gives a nervous laugh, "Heh, yeah, like I did." She stares at the tassel for a few seconds, a heavy sigh as she glances to Canterlot, snapping back to look at Scootaloo, a drawn out, "Anyway. So, that's momentum. You'll use some of that when you push yourself around on your scooter. After all, it's easier to push a light object around than a heavy one, right?"
Scootaloo nods, a little excitement in her voice, "Yeah."
"Okay, so, you can do the same thing with yourself, to a limited extent." Rainbow pauses, looking at her wings and giving a frustrated grunt, "Actually, never mind. Um, we should probably focus on something else."
"What? That sounded interesting, though!"
"Well, you see, you'd need to split your magic between that and flying, and... um..." Rainbow trails off, rubbing the side of her head and looking to the ground.
Scootaloo rolls her eyes, "Come on, dam, I know I won't be able to fly like you. But, I can still use that moment thing when I'm on my scooter, right?"
Rainbow's eyes light up, "Hey, yeah, that's right! So, let's see, momentum. Momentum." Scootaloo huffs, Rainbow saying exasperatedly to herself, "Come on, Rainbow, if you needed an egghead to explain something you'd go to the library. Or ask Doug. And you don't. You got this!" She turns, smiling at Scootaloo who gives a nervous smile back. "Okay, step one for your training! We're going to run into an apple tree."
Scootaloo's eyes bug out, looking around at the apple trees around them. "Um, is Applejack going to be okay with that?"
"Nah, it'll be fine. Watch!" Rainbow takes off, flying with her hooves pointed at the tree. Scootaloo winces, turning her head to the side as Rainbow smacks the tree with a loud bang. The crack of wood splintering echoes through the trees, a dazed Rainbow staggering over to Scootaloo. "See? Nothing to it." She wobbles a little more, shaking her head to try to clear the stars from her eyes.
Scootaloo raises an eyebrow, "Um, are you sure that's momentum?"
Rainbow nods, "Well, if you want an explain to egghead it then go ask your sire. Or something."
Applejack walks over, glancing at Rainbow before inspecting the tree she ran into. Apple Bloom is following close behind, watching her dam give a short glare to Rainbow. The earth pony mare says, "Okay, Apple Bloom, sometimes a tree will be damaged by a storm, or wildlife."
"Hey!" Rainbow calls, still a little woozy, "I resem... um... resent. Yes! I resent that remark!"
Applejack rolls her eyes, turning back to the tree, "And you'll need to use a bit of magic to help the healing process along. Now, go ahead and put your hooves up on the tree."
"Ah huh." Apple Bloom rests her hooves against the tree, closing her eyes and concentrating on the damaged section.
Applejack moves over to Rainbow as she says, "Now, try to focus on the tree and where it's hurting." Applejack stares at Rainbow, the pegasus looking back impassively. "Fortunately Bloomington the Second has pretty strong bark, or Rainbow might have gone halfway through and gotten stuck. Again."
"Hey, that only happened the one time!" Rainbow pouts, crossing her forelegs, "And it all worked out."
"Eeyup," Applejack says, a wink at Rainbow, the pegasus rolling her eyes, "Doug liked having to come out here and help, too. Now, what in tarnation made you want to charge one of my trees?"
"Well, I'm trying to explain momentum manipulation to Scootaloo. And a big part of that is cancelling out your speed when you hit something!"
"First off, that's not momentum. Not in the way you want it to mean. And you should start with something softer, like a pillow, if you want to practice that."
"Ugh," Rainbow moans, glancing to Scootaloo, "Okay, follow me." Scootaloo hops back on her scooter, the two heading back to the farmhouse as Applejack coaches Apple Bloom, the mare slowly getting more and more frustrated at Apple Bloom's lack of progress.
Rainbow opens the door, Scootaloo following inside. Rainbow pops into Doug's office, the human hard at work during the hot noon hours, Applebaum reading a book in the corner. Rainbow says, "I need a new pencil," as she snuggles next to him, her best puppy dog eyes on display.
"Another one?" Doug says, sliding out a box full of Wonderbolt themed pencils. He pulls one out, holding it up; Rainbow swipes at it, yelping as he pulls it out of her reach. She smirks, going down and getting ready to pounce as he says, "What happened to the last one?"
"Occupational hazard," Rainbow says as Doug hops out of his chair, his body lowering to a wrestling stance. "Demonstrating how a pegasus manipulates her target in order to safely execute a midair rescue." She pounces, aiming her hooves at his hand holding the pencil.
Doug grunts as Rainbow slams into him, one hand pushing against her shoulder while his legs dig into the wooden floor, trying to keep his back from pressing against the wall. Rainbow's hind legs push, toppling the two over and leaving Rainbow on top of Doug, one foreleg trapped between them and the other held against her side by his arm. She grins, her muzzle moving closer and closer to his face. Doug says, trying to keep his hold on the pencil, "And, what exactly happened to the last pencil?"
"Exploded." Rainbow moves down, a quick kiss before she starts pushing towards his outstretched arm, the pencil locked in her sights. "Like I said, occupational hazard."
Doug grunts as Rainbow pushes him down, her mouth finding the pencil. She looks over at Doug, a long wink as she takes half of the pencil between her lips, her tongue slightly poking out of her mouth as he lets go. Scootaloo moans from the doorway, "I'm not getting another sister now, am I? I wanted to learn about momentum."
Rainbow rolls her eyes, getting to her hooves and offering Doug a foreleg. "No, Scoots, not this time," as she pulls him up. "We were talking about momentum before, and Applejack suggested training with some pillows instead of apple trees."
"Ouch," Doug says as Rainbow rubs her muzzle, "Yeah, lighter things are easier to move around. And hurt less when they run into you. But, you can actually catch something when you're going really fast?"
"Well, sure," Rainbow says, motioning for Scootaloo to come over as she squats down, Applebaum looking up from her book with an excited look. "It'd be kinda hard to do a midair rescue otherwise. I mean, the g forces alone would knock out a pony who isn't ready for it."
Doug nods, making a curve with his hand, "Yeah, I remember seeing you make some incredibly tight corners, back when I first got here, that honestly should not be possible."
"Yeah! Um, maybe you can help me explain this," Rainbow says, a smile breaking out on Doug's face. "I mean, not the magic part, probably, but showing what would normally happen. With momentum and whatnot."
"Sure, I mean, this is all physics, right? Mass and motion?"
"Wait, that's what physics is?" Rainbow looks confused for a second, "Huh. Maybe I shouldn't have slept through that class. Not like I needed it, though!"
Scootaloo rolls her eyes as Doug slowly nods and says, "Sure. So, you want to throw some numbers in there or just talk in generalities?"
Rainbow considers for a second before saying, "So, I could perform a sonic rainboom. That's going, um, over seven hundred miles per hour. And it takes a really long time to turn, normally, but if I pour a lot of magic into it I can corner on a bit."
Doug twirls another pencil, "Yeah, so, a lot of things don't work well with zeroes, and the number you get will vary greatly by how close to zero you actually are. But with magic, all that kind of goes out the window."
"Yeah, like I said, I can turn on a bit, multiple times in a row if I have to, but my speed stays the same."
Doug shakes his head, mouthing 'magic' before he nods, looking at the two fillies. He pulls out a piece of paper, writing along, "Generalities it is, at least until we have some of the basics down. So, normally, your speed is how fast you are going. Your velocity is your speed, but in a particular direction. To accelerate, you change your velocity, either in direction, or in magnitude, or how big it is."
Scootaloo gets a somewhat spaced look, mirroring her dam, as Applebaum looks on excitedly. Doug continues, "Turning on a bit - and I've seen Rainbow do it, making a right angle contrail - is incredibly hard. Without magic, the acceleration required is massive. You need to completely decelerate your speed in one direction and then accelerate in another direction. You can do that simultaneously, or at the same time, but then you have an arc instead of a right angle. A circle, or a piece of it, like a curve."
Rainbow nods, "Yeah, that's not what happens. I just decide to go in a certain direction, and burn some magic, and there I am! It's practically required for some stunts and fog obstacles courses." Rainbow glances over as Scootaloo gives a dejected sigh, "Hey there, sport, it's okay."
"Uh, yeah!" Scootaloo says, a bit too much passion in her voice. "I'm fine, Rainbow!"
Doug shakes his head, "Yeah, I don't know how much we'd be able to figure out, at least without a lot of testing, but there are a lot of things that you can do without magic." Applebaum looks very interested, moving closer to look at Doug's drawings. Scootaloo hesitates, torn between pushing her dam to give her more practical training and finding out more about the non magic side of things. The three ponies settle down as Doug begins going into the math behind the equations. Scootaloo rubs her head, her brain already starting to hurt a little as Rainbow begins softly snoring next to her.