This is a perfect video in so many ways and extremely relevant to our lesson for the day!!

So we’ve all used the idiom “it’s just like riding a bike” in regards to an action that has become second nature to us. But our primary mode of recreational transport as young people exemplifies one of my favorite physical principles, Pure Roll.

Pure Roll is commonly referred to as “rolling without slipping.” In this situation we see a specific relationship develop between speed, v, of the CoM and the angular speed, w, of the wheel’s rotation, v = rw. The top of the bicycle wheel and the bottom are going this same speed, v = rw, but in opposite directions. Now, if we add in the velocity of the CoM, we find that, at any instant, the top of the wheel is going twice as fast as it’s center and the bottom of the wheel is at rest with respect to the ground! Whoa!! Here, the force of friction does no work because there is no relative motion!! But friction does ensure that a portion of the total kinetic energy is rotational kinetic energy. Now, please enjoy this edition of Darren and the Tiger concerning Pure Roll.

Ok, so I would like you to have a go at this scenario from the workbook in the next couple days. It is a great example of crossover concepts!! If you use Conservation of Energy, Rotational Inertia and your qualitative reasoning skills you should do great!!

Also, use your same skills to answer this question: If my Beatles record has a mass of 125g, a radius of 30cm and spins up to 33 1/3 rpm in .80s, what is the power delivered to the turntable??

Thanks so much everyone. It was so awesome to see you these past couple days. I will be doing more problems during class time using the screen share so let’s keep the momentum going!!

Mr. C

Welcome to the first episode of Physics Clas!! I truly hope you all are doing well and I wish I was going to school in the morning to see your happy faces!!

In the blog, I simply wanted to take a breath and go back to some simple concepts about momentum, its conservation and review some basic problem solving techniques with individual objects before we moved forward into collisions. So, I hope it’s helpful and sort of resets us as we move forward. I’m still working on my camera placing because iMovie shrinks the frame a wee bit but overall I’m pretty psyched about the video, except for my hair!! If you could comment on the sponsor of the episode (there is a little commercial in there) that would be great!!

So, we remember that momentum is equal to the objects mass times its velocity (p = mv) and that momentum is going to be conserved as long as there are no external forces acting upon the object. Also, since velocity is a vector, so is momentum which means it has a magnitude AND a direction. Finally, the impulse-momentum theorem states that the force applied over a time interval is equal to the change in momentum, (Ft = (delta)p, with delta implying “change in”).

So here is a question for you wrap your head around that touches on all the bits from this episode.

(1) A sudden gust of wind exerts a force of 10.0 N for 1.2 s in a direction opposite to the flight of a red-tailed hawk, whose speed was 5.00 m/s before the gust of wind. As a result, the bird ends up moving in the opposite direction at 7.00 m/s. What is the mass of the hawk??

Have fun!! Thanks again!! Y’all are amazing!!!

Welcome to the the Physics Clas blog!! I hope you’re all doing great!!

In this episode, I simply wanted to reacquaint us with Rotational Inertia or the “Moment” of Inertia (I). So I go though the bird/insect scenario again and I review the frisbee problem because many were absent and I didn’t go over it with the second group. Now, the video came out good except it shrinks a little when you put in in iMovie so the top couple lines are chopped on the problems but I read them out loud. So please forgive me as I navigate the precise placement. I hope you find it fun (there’s an outtake right at the beginning) and if you could comment on the sponsor of the episode (there’s a little commercial in there somewhere) that would be great!!

So, after I review Moment of Inertia, I talk about how how we can use the principle of the Conservation of Energy for an extended object that is rotating as its center of mass is moving through space. In such a situation, it turns out that we can write the extended object’s Total Kinetic Energy (K) as the sum of its Rotational Kinetic Energy (Kr) and its Translational Kinetic Energy (Kt). Specifically, the movement of the CoM and the rotation around the CoM!

Here are the two questions I would like you to have a go with!

(1) Three beads with masses m1<m2<m3 are each placed on a rod at distances of La<Lb<Lc from the axis of rotation of the rod with a rotational inertia of Irod (meaning the rod itself has a rotational inertia that is part of the total). Express the smallest rotational inertia of the system in terms of Irod and the masses and locations of the beads.

(2) A potter’s flywheel is a circular concrete slab, 6.5 cm thick, with a mass of 60.0 kg and a diameter or 35.0 cm. The disk rotates about an axis that passes through its center, perpendicular to its surface. Calculate the speed of the slab about its center if it’s Rotational KE is 15.0 J. The (I) for a disk is 1/2mr^2.

Thanks so much everyone!!! Y’all are simply amazing!!

By chronicling Richard Bobby and Richard Cheney, Adam McKay proves his subject versatility. Yet, the longtime funnyman’s recent lean toward quip documentary-esque pictures is noteworthy and confusing. And Vice is beguiling, like one of Cheney’s flies on the river, but is it good?

The scope of this story is not undersold. We all know the history. It comes down to this style where everything stutter-steps between timeline hops and actual footage hits along with text screens and, you guessed it, extensive and unnecessary fourth wall breaks. Here, Cheney (Bale), is likened to a conniving bull surrounded by people intimidated by him. But after each aforementioned film trap, we become less interested.

With Bale’s physical transformation notwithstanding, the appeal of this film is W (Rockwell). Let’s face it, Bush’s peculiarities and drawl are entertaining and Rockwell convinces you that he is him. He is spectacularly in over his political head and his yeehaw shtick is endearing. But the most memorable bit might be Alfred Molina offering up constitutional gaps on the menu as a restaurant server. And that these thirty seconds are so memorable speaks to the rest of the show.

Vice doesn’t quite grip us, tallying 2.84 napkins out of 5.

In this edition, the friendly Spidey-verse presents a super-heroic homecoming for comic animation. Amidst the drastic CGI of the current MCU, Lord and Miller find pace and spectacle in the timelessness and beauty of the cartoon. And we are all caught up in the web.

Miles (Moore), looking to temper the discipline of his police officer dad (Henry), turns to his cool Uncle Aaron (Ali) with confusion and discovery to ensue soon thereafter. Miles’ character is just perfect; both bashful and charismatic, dressed in classic Jordan 1s and offering a rejuvenating spirit. And, with Aunt May showing off her own sense, this picture overflows with style points.

As dimensions are crossed and the layers of the multiverse revealed, an array of Spideys appear including Gwen (Steinfeld), Miles’ petite crush, a fabulous nod to Anime with Peni Parker (Glenn) and the incomparable Spider-Man Noir (Cage) who stumbled right out of Casablanca to garner high FC praise. And this eclecticism brings a fervor and originality to a story that has seemingly been told many times before.

Commingling classic comic book speech bubbles and onomatopoeia with innovative animation, this film finds itself in the FC Elite-verse, tangled up in 4.83 napkins out of 5.

Stevie McQueen, a prince of enduring story, rules over this dowager heist in which our eponymous character inherits the rubbish left behind by the shady monarch. And in this midst, we struggle to focus as the plot hits keep our heads spinning.

Veronica (Davis), driven and disparate, hatches up a revenge, or possibly a self-preservation, schema to assuage the Widows. And here, we are introduced to the film’s zest, Alice (Debicki) and Linda (Rodriguez). Alice, acquiescent in all facets of her life, enjoys a certain freedom in the crew. Linda, a mom, apprehensive at the start, finds commitment in the potential of the payoff. And, individually, they ignite their sharp intellect and improvise, propelling the gutsy plan forward.

The men, well, meh. Jack (Farrell) and Harry (Neeson) cannot help but lapse into character. And this is alright, by all means, but it’s sideways from the film’s desired cerebral identity. And for the most part, we just wanted to get back to the ladies. Yet, from the lot, Jatemme (Kaluuya) conjures that wonderful disdain that shields the other males’ flaws.

McQueen, fittingly, overstuffed this Thanksgiving effort. But, on many levels, Widows endures to the hymnal of 3.4 napkins out of 5.

Bo knows YouTube. As a comedic lyricist, Burnham certainly toys with convention as his peculiar piano rifts garner laughs and hits. Yet, he uploads the opposite perspective in Eighth Grade. And this irony cradles a bustling narrative in an online world.

Kayla (Fisher), reticently slogging through the end of middle school, whips up a series of analgesic videos with an unwatchable tagline to achieve any sort of recognition. The video cut-ins introduce the chronological and fraught happenings during the final week sprinkled with playful intrusiveness from dad, Mark (Hamilton), as his acknowledgement of her anxious irrationality is aces; especially when she is about to throw all her hopes and dreams into the fire.

Burnham does well to introduce typical adversarial situations that a timorous kid could encounter, including an attempt to rise above the raised noses of the popular girls, Kennedy (Oliviere) and Steph (Mullins). It’s a bit of box ticking and scene stuffing but the kids are spot on. And Kayla finds her acceptance within the unexpected comfort of her humorous interactions with Gabe (Ryan).

As we know, a film reliant on screens on the movie screen is tricky but Eighth Grade cleverly scrolls through 3.79 napkins out of 5.

FC icon Tommy Cruise knows not the color of a green screen. The palpable relief upon realizing his health after flying over a car hood infuses Fallout, and the entire MI series, with a beautiful authenticity. And, as he leaps across tall buildings in a single bound to stop Superman, or, well, the guy who plays him, we applaud.

The Apostles, disciples of the Syndicate and bent on creating a new world from chaos, now possess plutonium owing to Ethan Hunt’s (Cruise) unbridled devotion to his friends. Á présent, Hunt and the IMF find themselves in a bit of a cornichon with our hero spinning around the Arc de Triomphe while evading actual police.

And let’s two-face it, Ilsa (Furgeson) and her seeming alliance to every faction and organization is the new story. She is selfish yet compassionate; as brutally honest as she is shady and her relationship with Ethan teases from the many chicanes the film enters.

Ultimately, Chris McQuarrie’s return as director lends continuity to character, story and style that we hold onto while all has gone, or is going, haywire. In making the impossible barely possible, Fallout rises into elite status with 4.76 napkins out of 5.

Innovative ideas are paramount here at FC HQ and Brad Bird’s genius in teasing a sequel that he might never actually create received high praise around our water coolers. And Incredibles 2, though still excellent, discovers the difficulty in recreating the bravado of a winded and overweight superhero in his extra medium super suit.

As our raccoon-eyed heroes, The Parr’s, hurtle further out of favor in the public eye, Helen/Elastigirl (Hunter) gets the call from Winston (Odenkirk) to prove the worth of Supers. Evelyn (Keener), the sis, has some pretty obvious tricks up her tech-savvy sleeves. With hilarity, the buddy-hero chumminess of Lucius/Frozone (Jackson) and Bob/Mr. Incredible (Nelson) is marvelous while the teenage angst of Violet (Vowell) is bullseye.

Even as Lucius channels his inner Jules, we wait patiently for the perfectly placed mock or spoof underscoring the gibberish from Jack-Jack (Fucille). But, at times, the artfully crafted Pixar genius flies into the wind of the relentless Disney storm and folds like a paper castle.

Yet, with the undeniable brilliance and creativity of this narrative, it allows for a sub-Parr film to land on the precipice of elite status, despite a villain named The Screenslaver. Incredibles 2 captures 4.36 napkins out of 5.

We are absolutely busting here in the FC Paddock as Jurassic World finds a way to crack through the shell of our shabby bias. Fallen Kingdom is investing since it takes us off the island, engineers new story lines and endorses new characters. And it cleverly reminisces the original, rousing more smiles than eye rolls.

When rain falls on Isla Nublar, DNA mischief is afoot and this ominous tension is quite the relief, for us. Claire (Howard) has undergone a complete character flip while her dalliance with Owen (Pratt) seems in doubt, or, at least, funny. So, from the outset, we greet morality, humor and relationships; the Jurassic triple play. And that’s how you reignite story excitement.

Lockwood (Cromwell), gripping his amber handled cane, is neatly assuaged into the history but it is his granddaughter, Maisie (Sermon), who owns this story. Wise to the shady ways of Mills (Spall), Maisie wiggles through the nooks of the estate, gaining an advantage and our favor. Honestly though, despite the excitement, the untapped dinosaur black market lacks the zest of a great villainous plot.

Fallen Kingdom provides enough talon-tapping fun to restore our faith in paleontology, preserving 3.49 napkins out of 5.