Reference Frames

My cousin put her soccer ball on the floor of our car. When we started moving, she was surprised when it hit her on the shin. She didn't understand why the ball moved, after all, there was no force being applied to it. I told her that it was simple physics!! It looks like the ball moved on its own, but that's according to the reference frame inside the car. If a person on the sidewalk could see through the car, they would think the ball is staying in place, and the car was moving!

Buoyant Betting

A bunch of my friends were hanging out at the park. The girls were sitting on the merry go round, laughing at the boys who were having a macho contest. They wanted to see who could carry the heaviest cement brick across the field. Finally, they got to the heaviest block, and neither of the could carry it all the way across, dropping it on their feet and yelling out in pain. Laughing, I bet that i could easily carry it the distance of the field. They happily took the bet. We drove down the street to the beach and I told them to throw the rock in the water. It was very easy for me to carry it the distance of the field. I collected my winnings and thanked physics! Instead of carrying the whole weight of the rock, I was helped with buoyant force (equal to the weight of the salt water displaced) So I only needed to carry W-Buoyant Force. Yay!

Frisbee Fysics

so basically right now i pretty much think bhasha is the most awesome person ever!... like seriously though can anyone contest that? ..well not me
anyways, i think that frisbee is pretty cool too, not as cool as bhasha of course..but close enough.
well i thought id go and check out the illumin magazine which doc had left us a message about, and i found an article about my second favorite game, after tennis, FRISBEE!
well basically, a frisbee not only stays in the air when we throw it, it rotates as well.
there are three forces acting on a frisbee, weight=mg down ,lift casued by air moving below, and drag caused by air resistance.
a frisbee eventually falls because the air running over the top, becomes more forceful than that which is lifting it.
now rotation occurs, because the lift force on the frisbee is not directly below, but because one throws it at an angle, it is coming from the side at an angle.
it keeps spinning because the torque caused by the lift tries to flip the frisbee over in a certain direction, but as the frisbee moves the torque starts acting in that new direction, keeping a constant balanced rotation.
and why does a frisbee have ridges? well that's because, the ridges form a sort of minor turbulence with the air which keeps the lift air force acting on it longer, thereby allowing the frisbee to fly farther!
wow what a great game frisbee is!

Merry Go Round and Round

My friends and I felt like being little kids again. So we went to the park and played on the merry go round! We spun my friend, who wasn't allowed to hang on to anything faster and faster, trying to throw her off. It was exactly like physics class! Because weight (mg down!) and normal force were equal and opposite, friction force was the only thing preventing her from flying off. It was also the centripital force (mass times veloicty squared all over radius). If the static coefficient remained constant, we just had to make the velocity high enough to overcome the friction force. We did! Thanks to physics, we had a good laugh. go physics!!