Flippin Awesome

Happy Thanksgiving everyone! I hope you all are fat now from all the turkey stuffing, and pumpkin pie. Did you watch the Summer Olympics in China two years ago? But, most importantly, did you watch gymnastics?? If you did, you were probably wondering why the gymnasts could do double tucks (when legs are tucked in) and double pikes (when legs are straight but body bent at hips) in their tumbling passes but not layouts (when body is straight). In this video, you can see that I am demonstrating a standing back tuck. And I can tell you, as a gymnast and a cheerleader a tuck is much easier than a layout. In order to execute a more precise back tuck, the legs must fully be tucked in as close to your body as possible. If my legs were out or floppy, it would be harder to land it. This directly relates to torque. Remember? Torque equals the distance from the axis times the amount of perpendicular force. When my legs are tucked in the radius from the axis, my hips, is shorter therefore the amount of force needed to make a complete rotation is less (easier), compared to if I was to do a layout (harder).

Piggy back Rides

Thanksgiving break is coming!! I cant wait! Actually, I cant wait for college apps to be OVER!! i see the light in the dark tunnel I am in right now. So here we have a picture of little 100-pound Jill piggy backing way-over-100-pound Iris, me. If you've been following my blogs, you should know by now that the normal force exerted on Jill by the ground is much greater with me on her, because of intense increase in weight. You may also notice that Jill is standing on one leg, which should make it even harder for her to balance. You may wonder why doesn't she fall over? It's because her upper body or center of mass has shifted over her left leg. Since Jill's (and every human's) center of mass is above her legs or support, she will always be in an unstable equilibrium. This is why we are constantly shifting our weight to different areas in order to gain (as close as possible) stable equilibrium. Virtually any person, weak or heavy, small or big, should be able to handle any amount of weight if they know where their center of mass is.

Handstand!

Physics and gymnastics go hand in hand. I found this out this week when learning about torque. Maybe next week I'll show you why a layout is more difficult than a tuck or a pike. Anyways, when I was younger and I did gymnastics, we used to walk on our hands in a handstand across the entire floor with our legs straight. But this position I did here is easier than a normal handstand because my legs are able to help me balance on my hands. Think of my body as a seesaw and my legs are the two ends and my upper body is the center. If my weight shifts to either leg more than the other, it will create a torque and my legs will rotate from my hips. However, if I keep my weight equally balanced, there will be no or little torque applied to my body. Torque is equal to the distance from axis to force multiplied by the force applied to the object. If more weight is in my left leg then the torque will be positive because my legs are rotating counterclockwise and vice versa.

Ferris Wheeel

Another week gone, senior year is going by way too fast, yet too slow. I want to graduate already!! College apps are a pain in my butt, and also AP Physics.. Anyways, who's been to Disneyland?! I hope everyone; its the happiest place on Earth! :) If you haven't, you've probably at least been on a ferris wheel right? Have you ever wondered what keeps you going in circles? Well, it's because of the centripetal force going radially inward. The cart you're in while on the ferris wheel is being pulled radially inwards from the tension of the spokes (connected to the center.) However, there are different forces acting upon you, as a rider. As you board the ferris wheel (at the bottom), the normal force is greater than your weight ("heavy" feeling). Therefore the net centripetal force is the normal force minus weight, equalling the mass x velocity squared divided by the radius of the ferris wheel. And at the top of the ferris wheel, your weight will feel greater than the normal force("light" feeling). So then, the centripetal net force would be weight minus the normal force, equally the same expression as before. This "light" and "heavy" feeling is the same kind of feeling you get when you're in an elevator.

Going in Circles

My last homecoming. So fun but I cant believe its over. I hope everyone had a fun Halloween! I know I did! :) I was Belle, from Beauty and the Beast, wh0/what were you?
So, new concept of the week: rotation. I chose this picture because it shows rotation in the wheels and the actual bicycle going in circles. The wheels have a uniform circular motion. The bicycle ideally should have a uniform circular motion if I'm steering in a perfect circle. The period, or one revolution, of the wheels and the bike vary depending on how fast I'm pedaling. The centripetal acceleration of wheels are directed towards the center of the wheel, whereas the centripetal acceleration of the bicycle is directed towards the center of the circle I'm pedaling in. Remember last week when I explained how momentum worked? Momentum can also be applied here. As you can see Lumi is riding on the back of the bike with me. If we were going down a hill the momentum of the bike with Lumi and I would be greater than the momentum of the bike with just me because of the larger mass. Essentially, almost every physics concept I have explained to you can be applied to this picture: normal force and gravity, friction, work, etc.