Chapter 9

Claire’s turn:

Near the end of the second week of school, I started a study group in one of the library meeting rooms. There were just a few kids looking for math help during the first couple of sessions, but by the end of the next week people were showing up for help with all the STEM classes, even ones I’d just tested out of, including calculus and physics.

“I’m confused about centripetal force and centrifugal force,” one of the students, Mike, said to me near the end of September.

“Join the crowd,” I said with a fake groan. Some of what I’d read about the concepts was pretty obscure, but one book had some examples that made sense to me so, I thought I’d try them out.

“First, centripetal force is fairly easy. It’s the force that keeps something moving in a circular path. So if you’re swinging a ball on a string, the string is pulling the ball. That pull, the tension in the string, is the centripetal force.”

“Huh? I thought applying a force resulted in a mass being accelerated? You can swing the ball at a constant speed, so where’s the acceleration?”

“The thing to remember is that acceleration isn’t a change in speed, it’s a change in velocity. Velocity is a vector that gives both the speed and the direction. Even if the speed, denoted by the magnitude of the vector, stays the same, changing the direction requires an acceleration. So, the fact that the direction of the ball is constantly being changed means there’s a force acting on it, right?”

By that point, a couple of other physics students had joined us, looking just as puzzled. “You all remember the part about a body in motion continuing at a constant speed, in a straight line unless acted on by an external force, right?” They all nodded. “The ball isn’t continuing in a straight line, so an external force has to be acting on it, right?” They all nodded again.

“So, if we’re looking at the ball on a string, the ball would keep moving in a straight line if the string wasn’t pulling it, constantly changing its direction. The tension in the string, then, is the centripetal force — the force that is continually changing the direction of the ball’s velocity vector.”

Shawn, one of the other students, said, “So, why didn’t Peterson explain it that way?”

I just shrugged since I wasn’t in the class. “Is everyone clear on that? Good, because now it’s going to get strange. Centrifugal force isn’t actually a force.”

“That’s what Peterson told us,” Shawn said. “Then he turned around and said it’s an inertial force, which sounds like a force to me. He tried to explain it, but I’m pretty sure I’m not the only one who didn’t understand his explanation, and he wasn’t willing to give it any more time.”

I thought for a second, then said, “Let me guess, he talked about things like non-inertial frames of reference and rotating frames of reference, right?”

Everybody nodded. I just rolled my eyes.

“Let’s try this instead. Imagine you’re the passenger in a powerful car sitting at a stop sign. Suddenly, the driver floors it. Don’t worry about the flashing blue lights behind you — they’re the driver’s problem.” Everyone at least smiled at that. “Instead, think about what you feel. It feels like there’s a force pushing you back into the seat, right?” They nodded. “But there isn’t, is there? The only thing acting on you in the line of travel is the seat, which is pushing you forward, not back.” After a few seconds they all nodded.

“What you’re feeling is the result of your inertia, your resistance to being accelerated. That’s why it’s sometimes called an inertial force. To me, it seems confusing to call it any kind of force right after saying it’s not a force, and none of us need the confusion, so I’ll just keep saying it’s not a force. The whole non-inertial frame of reference thing just means the frame of reference is accelerating, that’s all. In this example, think of the car as the frame of reference.

“Now, it’s exactly the same for centrifugal force. It feels like there’s a force pushing you away from the center of rotation, but that’s just your perception of inertia resisting the centripetal acceleration that’s pushing or pulling you toward the center.”

Suddenly, Mike’s eyes lit up. “I read a story once, I don’t remember the name, where they had a space station and part of it rotated to simulate gravity.”

I nodded and said, “It’s been used that way in a lot of science fiction stories. You’d experience something pushing you down, and it would feel like gravity, but instead it would be the surface pushing you up toward the center of rotation.”

At that point everyone seemed to get it, but I added, “It’s always going to be natural to think of it as a force because that’s what it feels like, which is why they have fancy names for that sort of thing — fictitious force, inertial force, centrifugal force. Whatever. As long as you remember that it’s not actually a force for class, you should be fine.”

Over dinner one night in mid-October, Grandma said, “Claire, Miss Green wants to meet with us tomorrow during your first free period unless you have something else going on. She’d like you to be there, as well, Charley.”

“That’d be fine by me, Grandma,” I said. “Did she say what it’s about?”

“No, just that you’re not in trouble, but she’d like to get something started as soon as possible.”

“I’ll be there, too,” Charley said.

After everyone was seated the next morning, Miss Green asked me, “You’re planning to go to college, correct?” I nodded. “Have you given any thought to which school you’d like to attend?”

“Do you think I could get into the UW¹? (see below for noted items) I’ve read that they have a great computer science program,” I said.

She chuckled and said, “Getting into the UW won’t be a problem. The computer science program is very competitive, though, so that isn’t a sure thing. Still, given your grades, I think it’s likely you’d be accepted. Is there anywhere else you’d consider going?”

I shrugged before saying, “I haven’t thought that much about it yet. Maybe Bellingham², but I’m not sure about their CompSci program. I’d rather not go to a religious school, so UPS³ and PLU⁴ are out, not that I really want to go back to Tacoma anyway. Sean suggested I might want to go to OSU with him and Tom, but I’m not sure — I know they do computer science but, well, so does the UW, and it’s a lot closer to home.”

“Given your grades, if you’re thinking computer science, you might also think about some place like Stanford or Caltech,” she said.

I didn’t need to see Charley stiffen to know that she didn’t want to go back to California. Besides, I’d done some research of my own — the age of consent in California was eighteen!

“No, I really don’t want to go to California, Miss Green. Grandma, Grandpa and Charley are all here, so if I can go to the UW, then that’s where I’d like to go.”

Turning to Grandma and Grandpa, Miss Green asked, “Mr. and Mrs. Lewis? What do you think?”

“We’re a mixed family,” Grandma said with a snicker. “I’m a Cougar⁵ and Bill’s a Husky¹, so our loyalties are divided. From what I understand, though, the UW’s computer science program is top-notch, and it would keep her closer to home.”

“Miss Black? I know you don’t have any official standing, but I’m sure your opinion will be important to Claire.”

“I agree with you that she could go to any of the California schools, or pretty much anywhere else for that matter,” Charley said. “Still, given the reputation of the UW’s computer science program, I don’t know that she’d gain a huge amount, even going to some place like Stanford or MIT⁶, so I can’t fault her for wanting to stay close to home.”

“Okay, then let me talk to some people I know there who might be able to help, since I think Claire deserves some special consideration.”

¹ UW - University of Washington, typically pronounced Youdub, grads are known as Huskies after the mascot
² Bellingham - Location of Western Washington University
³ UPS - University of Puget Sound
⁴ PLU - Pacific Lutheran University
⁵ WSU - Washington State University, pronounced Wahzoo, grads are known as Cougars after the mascot
⁶ MIT - Massachusetts Institute of Technology

I was thrilled that virtually everyone at school respected the fact that I was engaged. It was something I’d worried about, at least a little, from the moment Charley first put the ring on my finger. I knew that even the kids at Mt. Tahoma were a lot more respectful than most people gave them credit for, but here? In a small town, where everyone knew everyone else? No, stepping way out of line wasn’t tolerated here, even by the students.

Still, they say there’s one in every crowd and Steven Evers, Stevie to everyone in the school, was ours. He’d kept after me, but quietly and discretely, so I couldn’t really do much about it ... well, except slugging him, but that would’ve gotten me in trouble, so I resisted the temptation.

Then one day he started in on me as I was walking home.

“Listen, I don’t care if you’re engaged,” he said, just loudly enough for me to hear. “I think you’re hot, and I want some of that.”

Ah, witnesses. “I already told you no,” I said, loudly. “What part of ‘no’ is too difficult for you to understand?”

That would’ve been a good time for him to leave. Instead, he raised his own voice and said, “And I told you I’m going to get some from you. What part of that is too difficult for you to understand?”

If he’d been paying attention to anything but me, he might have realized that Shawn had just come up behind him. Shawn was in my study group, working on physics and calculus, but he was also the captain of our wrestling team and expected to vie for state in the 220 pound class. Given that I thought I could probably pound Stevie, he definitely wasn’t in Shawn’s league.

Shawn just dropped his right hand on Stevie’s right shoulder and squeezed. It looked like Stevie tried to pull away, but Shawn barely moved, and he didn’t let go. “You know, Stevie,” he said, “it sure sounds to me like you’re threatening to sexually assault a friend of mine.” Stevie groaned, then suddenly got louder, so I assumed Shawn had tightened his grip. “That’s not a nice thing to do. In fact, even just threatening to do it, is pissing me off. You know what happens when you piss me off?” He used his left hand to quickly grab Stevie’s left wrist, then twisted it up between his shoulder blades. He must have jerked it then because Stevie’s feet came all the way off the ground for a second and he screamed.

Just then, Principal Wells walked up and calmly said, “I assume there’s a reason for this display, Mr. Kincade.”

“Yes, sir, there is,” Shawn said. “It seems someone was trying to force himself on Claire and, well, I like her — she doesn’t treat me like I should be dumb just because I’m a wrestler. I was just attempting to convince this steaming bucket of pig shit that it would be a really bad idea to bother her anymore.”

I was frozen in shock. Shawn hadn’t released Stevie and Mr. Wells was just standing there talking to him!

Then the principal squatted down so Stevie could see him. Addressing him in a light, genial tone, he said, “Well, well, well, Mr. Evers. I understand that Miss Lewis has made several friends here at her new school. It looks to me as though you just upset one of them. Such a pity that school property ends on the other side of the street, isn’t it? Why, if Mr. Kincade did this on school property I’d be obliged to punish him, and that would be terribly unjust. Instead, I’d just like to assure you we’ll all be keeping a closer eye on you from here on out. Isn’t that nice?”