# mgiamartino

Members

19

## Community Reputation

10 Good

• Rank
Junior Member
• Birthday 06/20/1996
1. ## The Physics of Swimming

As summer gets closer, the weather gets warmer and everyone itches to get outside. One of my personal favorite things to do on those hot summer days is to go swimming! So many people enjoy it and it is something that they do all the time, but the majority of people don't stop to think about all of the physics that is involved in it. And there is a lot! First, the most obvious is the difference in gravity. When you are just walking around normally, you stay on the ground. You never begin to float towards the sky because of the force of gravity on earth. The force of gravity is 9.81m/s^2. However, as you may know, when you are in a pool or the ocean it is very hard to stay on the ground because there is nothing pulling you down. But you are still on the earth... so how can that be possible? Although the force of gravity is the same, there is an additional force acting in the water called buoyancy. This means that when an object is put in water, it will displace the amount of water equal to its volume. This is why objects appear to be lighter when they are in water. There is also a lot of resistance in water. Water is about 1000 times more resistant than air and about 91% of a persons energy is lost through drag. Therefore, when swimming competitively, swimmers need to maximize their streamline. They can do this by wearing swim caps. As you can see, there is a lot of physics in swimming. So next time you jump in the pool, think about all of the physics that is going on! Thanks for reading
2. ## How does Lightning Work?

Very interesting! Cool topic
3. ## Master Assassins

that's so cool! great post
4. ## physics of bungee jumping

That's so cool! Awesome post
5. ## physics of golf

Great post! The pictures really helped
6. ## The Physics of Roller Coasters

As summer approaches, people get more and more anxious to finish up with their classes and school work. They want to get out of the hot, sticky schools and get out into the sunny fresh air. I know I do! Going to amusement parks like Seabreeze or Darien Lake is a great way to pass the time and have fun too. Although you may not realize it, many of the rides there have a lot to do with physics! One of the most popular rides are roller coasters and that involves tons of physics. First, there is a lot of potential and energy that is stored and used. There is a chain that is used to pull up the roller coaster cars to the top of the hill. This is creating the potential energy. Potential energy is energy that is waiting to be used and is currently being stored in whatever object applicable to the situation. Once the roller coaster reaches the top of the hill, the chain releases the car and all of the potential energy is turned into kinetic energy. Kinetic energy is energy that is used during the motion of something. Gravity also helps with the cars kinetic energy by pulling them towards the ground. When the car is at the very top of the hill, that is where the potential energy is at its maximum. As the kinetic energy increases (as the car goes down the hill) the speed also increases. There is also a lot of work that is done in roller coasters. Work is the force that is used to move an object from place to place. The work that is done in this case, is when the chain pulls the car up the hill on the track. The work of bringing the car up the hill is done to overcome the force of gravity which is pulling the car towards the ground. Therefore, the more mass that the roller coaster had, the more work it takes to bring the car up the hill. As you can see, roller coasters have a lot of physics that is involved with them. So, next time you are riding one at an amusement park, you should think about all of the physics that is going on around you! Thanks for reading
7. ## Physics of PCX

Wow I never realized how much physics was involved in PCX! Next time ill definitely think of all this information when I go with my team, great job
8. ## The Answer, My Friend: is Blowing in the Wind

Great post! Loved all of the detail, good job
9. ## The Physics of Jump Roping

As a kid one of my favorite past times during the summer was jumping rope. My sister and I would love to go out with the kids from our neighborhood and do this for hours on end; we even knew all of the silly rimes that people sang! Little did we know, there was a great deal of physics that is involved in this activity. First, when jumping rope, one has to jump up and down to hop over the rope and this is because of gravity. The force of gravity lets the jumper come back to the ground after they leave it to jump the rope. If you wanted, you would even be able to calculate the distance from the ground you jumped. To do this, you would have to time how long it took to jump up (or down, but not both), you would know that the acceleration due to gravity is 9.81m/s^2, and the initial velocity is 0m/s. Once you have all the information you could use your kinematic equations to figure out how far off of the ground you jumped! In addition, when you jump rope there is a lot of centripetal forces acting on the rope. When you rotate the rope around your body, the reason it stays up in the air over you, instead of falling on your head, is because when an object is moving in a circle the forces acting on it push outward. The velocity is also pushing towards the outside of the orbit. This means that the rope that you are jumping over will always stay up over your head until it is stopped or the speed decreases. Now you see all of the physics that is involved with jumping rope! Thanks for reading
10. ## why do Iphone screens shatter so easily?

This is good information to know! I hope that I can avoid this happening to me
11. ## Physics of Sailing

Loved the diagrams, they were very helpful! Ive always wanted to learn how to sail

13. ## Bowling Physics

I liked how you explained how friction and potential energy have to do with bowling, good job!
14. ## Volleyball through physics

Great job explaining the way the acceleration and velocity fit into playing volleyball, I liked the video you added too
15. ## Diffraction

I have always hated it when my parents came upstairs at night and turned on the hall light while I was trying to sleep. For some reason, the light from the hallway would somehow get into my room while the door was closed and make it brighter. I never knew why the light coming from a small source like from under a door or through a little hole would light up an entire room or look so much bigger and brighter than it originally seemed to be. This was until recently, when we learned about diffraction. Diffraction is defined as the phenomenon that happens when a wave comes across an obstacle. What happens is when the waves pass through an opening, they spread out. The waves that get spread out the most are those that have the same wave length as the order of magnitude in the obstacle. The types of waves that can be diffracted can include sound, light, electromagnet (visible light), X-rays, and radio waves. Longer wavelengths and smaller objects help to provide maximum diffraction. Therefore, when my parents turn on the hall light and my room is lit up even though the door is closed, it is because of diffraction. The light from the hall is traveling through that little slit underneath my door and the waves spread out into my room. This is caused because the light wave is coming in contact with an obstacle and when this happens, the light wave just goes around the obstacle (my door) and spreads out which causes my whole room to light up.