# konneroakes

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2. ## Physics of throwing a discus

Their is a lot of physics in throwing a discus. A throwers body must move in a certain way to provide the maximum power to throw the disc. Throwers must spin to create centripetal acceleration and land in a way to wind up their hips. The hips act like a spring and the thrower pivots his/hip as fast as possible to launch the disc. Not only is power a factor but releasing a disc correctly is extremely important. The disc should be released at a 45 degree angle from the thrower. The disc itself must not be angled at 45 degrees so the thrower must raise his arm at a 45 degree angle to maximize distance and have the discus travel in the air at a 45 degree parabolic path. The thrower must also release the disc as flat as possible so wind provides very little backward force. A disc thrown perpendicular to the ground will fall very quickly because the force of air on the disc will be much greater over an area of an up and down disc as opposed to a sideways disc. With all of the proper technique a discus can be thrown over 200 feet. The world record is 74.08 meters (243 feet). This requires almost perfect form, and training but the art of throwing a disc is based completely on physics.
3. ## How to be good at Drag Racing

Typically before a drag race the drivers will spin their tires really fast. This converts Kinetic energy (the movement of the tires) into thermal energy from the friction the ground provides. The tire then is very hot and sticks to the racetrack very well. When the light goes green the friction between the ground and the tire is much greater than if the tire was cold because the hot tire expands and pushes into small bumps In the asphalt much more. The car can launch much easier and convert the kinetic energy of the tires movement into kinetic energy to actually move the car instead of spinning the tires and losing time. This is also typically why drag cars have thicker axles. If the tires don't spin a lot of force from the powerful engine will try to spin the axle and push the 3000 pound car very fast. A very thin axle will snap under the force so a good drag car typically needs a bigger, stronger axle as well.
4. ## Cars made "weaker" in certain areas for safety

Back in the 1950's cars weren't made with crumple zones. Cars were made with very simple, straight sheets of steel that weren't made to bend when they crash. So in certain situations ,like fender benders, these cars are great because the fenders won't bend and will break parts on the other car. However if someone smashes into a telephone pole the car won't provide a great enough impulse for a good chance of survival. In the 1970's the growing concern for car safety led to car companies creating cars with what are known as "crumple zones." These are areas made to bend so if a car smashes into a telephone pole the time a person has to experience the massive force is a few fractions of a second greater than before. This may not seem like a lot of time but such a massive force being extended just a little bit longer will have a huge impact and possibly a chance of survival in a massive collision. The acceleration the driver or passenger in the car experiences is significantly smaller. This is also a reason that seatbelts are required. A hard collision at a high-speed in a car without a seatbelt will cause such a massive acceleration to the driver that he/she will fly into (or possibly through) the windshield. Physics helped make cars significantly safer over the past 50 years.
5. ## Monsters Inc. teaches kids Physics

I had to babysit my younger sister and she wanted to watch Monsters Inc. Although the movie's plot may not be the most realistic the physics concepts of the movie are realistic. If you haven't seen the movie children's screams and laughs power doors so when a child laughs they can open up a door to the human universe. A scene included the main characters, Mike and Sully, having their door fall from very high up. Sully is a very big monster and Mike is very small but they both fall at the same speed as each other and the door. Although the weight of Mike, Sully, and the door is probably very different they all accelerate toward the ground at the same speed. This is demonstrated very clearly as the door falls sideways Mike manages to grab the handle and pull himself inside. Mike then musty pull Sully inside and add an additional force other than gravity so Sully accelerates at a greater rate into the door. This scene can help teach young kids physics and is sure to have sparked questions from parents. When my sister grows older I can explain this scene to her and give her a better understanding of gravity.
6. ## Why is it easier to open a pickle jar after running it under hot water?

Opening a tightly sealed pickle-jar can be tricky. There is a logical Physics explanation why running it under hot water can make it easier to open. If we assume it is your average glass pickle-jar with a metal top than heating up the jar will loosen the lid because the metal conducts more heat than the glass. This means the metal will expand before the glass gets the chance to expand the same distance, so as the metal expands the Force required to open the jar decreases. This may seem confusing because the coefficient of glass and metal doesn't change from simply heating it up; but the force of friction is equal to the coefficient of friction x the normal force between the objects. As the lid loosens the normal force the glass produces to push back on the lid is decreased so the Frictional force is lowered. Running the lid under hot water may make your hands slip easier as well because the wet metal on your hand might have a different coefficient of friction, so drying the lid and your hands is recommended.
7. ## The physics of stubbing your toe

Walking into a wall or a doorway and hitting your toe can be very painful. Their is a logical explanation for this pain. Walking requires a lot of energy because to walk you must produce friction with the ground with your legs. People swing their legs forward to take another step. When you swing your leg out into a wall and hit your toe, all of the force from the swing goes directly into your toe. It isn't the force that you supply that hurts your toe but the force the wall exerts back on you when you hit it. All of the force that you provide comes back into your toe and tests the strength of the bones in your toe. If enough force is put into the swing, the same amount of force will be exerted into your toe when you hit the wall and break your toe. After hitting my toes many times I've learned to slow down in my house.
8. ## The Physics of sitting

When sitting in a chair a lot of forces are acting on each other. As I sit in a chair the force of gravity multiplied by my mass determines the force acting on the chair. Although it seems I am only supplying a force onto the chair, the chair is supplying an equal, opposite force up on me to keep me from moving down. If the chair was not supplying a normal force back on me I would accelerate downwards to the ground at 9.81 m/s. The chair I am sitting in also supplies a force on the ground. The ground must supply a force equal to the weight of me and the chair to keep us from going downward. The normal force holding me and the chair up cannot be greater than the force me and the chair produce because if it did me and the chair would accelerate up into the roof.