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Everything posted by hannahz

  1. Speakers contain an electromagnet which is a coil of wire that the current flows through. First, it starts with a battery and then moves into the coil of wire. When the magnet vibrates the air molecules start moving and create waves. The waves then produce the sound that you can hear. Also there is energy transfer in a speaker. For example, the phone has electric and chemical potential energy because its a chemical reaction that causes the electricity to flow. Chemical turns into electrical and then flows through the wire. When the energy flows through the wire, it moves into a coil of wire which has a changing magnetic field because the song changes the frequency of the wire. However the magnet has a contestant magnetic field and when its placed against the coil of wires magnetic field, it allows the magnet to vibrate and in the end it makes sound.
  2. When a surfer is waiting to go, there are 2 forces that affect the surfer. For example, there is gravity which pulls the surfer down and normal force going up. If you were to find the net force it would be equal to 0. When surfing, it is important to maintain balance. When the 2 forces are in line and add to 0, then the surfer is stable. However if one slides backwards on the board, the downward force of gravity moves behind the normal force. Also when the wave approaches the beach, it is a transverse wave. This means that it is perpendicular to the direction of wave travel.
  3. During the spring and summer time many kids beg there parents to take them to a local playground or park. Or sometimes they have a play set in their backyard. Just like riding a bike, going down a slide includes lots of physics. For example, gravity is one of the most common physics element in riding down a slide. When someone sits on top of the slide, gravity is the force that pulls the person downward. Ever get that feeling that you're going to slide right down the slide the minute you sit down? That's because of gravity. Without the force of gravity, a slide would never work. Also, friction is another important element of physics in riding down a slide. For example, frictions works against gravity to slow someone down. Without friction on a slide, the person would accelerate way too fast and would probably result in injury. However if you were to ever go to a water park, some rides have water slides. The water on the slide reduces the effects of friction which in the end makes the person travel a lot faster down the slide. Therefore, if you ever want to go faster down a slide, reduce the effects of friction that the slide has with your back.
  4. As spring is starting to approach us, many kids want to get out and start riding their bikes. However, what some kids don't know is that riding a bike involves physics. When you are riding your bike, you start by going very slow; however, as you begin to pedal fast, you speed up, that's called acceleration. When you start traveling at normal speed, you don't have to continue pedaling as hard. This means that you're just traveling at a constant speed which means that you're not accelerating. Also, if you stop pedaling, the friction of the tires will start making you slow down and go slower. Therefore the next time you're riding your bike, you will know that acceleration and friction are involved!
  5. When riding a roller coaster, gravity is one of the main forces. When the cart on the roller coaster travels to the top of the hill, its the acceleration due to gravity that brings it back to the start. When the cart gets to all the way up to the top of the hill, gravity ends up pulling it down. The cart starts at a slow pace but gets faster as it approach's the bottom. As it begins to climb to the next hill, the speed slows down. This is because the acceleration due to gravity is 9.81 m/s^2. As the roller coaster cart begins its fall from the lift, its velocity increases which causes the cart to gain kinetic energy. So therefore the faster the cart moves, the more kinetic energy it gains.
  6. With the superbowl coming up, football is all thats been watched at my house. As i was watching one of the games, i noticed that there is a lot of physics during a football game. For example all three of Newtons laws are used during a football game; however the one that i noticed the most was newtons first law. Newtons first law says that an object in rest remains in rest unless acted upon by an outside force and an object in motion remains in motion unless acted upon by an outside force. For example, in football the wide receiver catches the pass from quaterback and starts to run down the field. However the wide reveiver would be able to make it all the way down the field to score a touchdown if no one tackled them. But because the other team wants to make sure they dont score a touchdown, they tackle him. This shows newtons first law becasue the wide receiver reamins in motion until another player goes and tackles them. Therefore newtons first law can be applied to the game of football.
  7. It comes a time when everyone turns 16 and it's finally time to get behind the wheel and start driving.After taking a closer look, I realized that Newtons Third law applies to driving a car. For example, Newtons third law states that every action has a reaction. This applies to driving because when someone is driving the action is when the car is pushing agaisnt the road and reaction is when the road pushes agaisnt the car's tires. Now lets say you (by accident) hit a person, when you hit that person, the person also hits the car. Or when you hit a pole, the pole also hits the car. Also when you push the gas pedal, the gas pedal pushes back onto the persons foot.Therefore, Newtons third law applies to driving a car.
  8. There is more and more snow that is falling from the sky and many people take the chance and go outside and go sledding. However what many people dont realize is that sledding involves alot of physics. For example, Newtons first law, says that an object in motion will not change unless acted upon by an outside force. In other words an object at rest will stay at rest until a force causes it to move and an object in motion will stay in motion until a force acts on it and causes it to stop. For example, it takes a pretty strong push to get you with your friend on the same sled moving, but once you get speed you'll keep going even at the bottom of the hill where the run flattens out. It takes much more force to stop you and your friend on the sled than to stop an empty sled.
  9. Almost everyone does it but not everyone knows the acutal effects of texting and driving. Most people are told that being distracted while driving is never a good thing and to always avoid it but do people really know how much texting can affect ones reaction time? If you take an average speed of 30 miles per hour, the average stopping distance would be around 7.5 meters. However if you add in the distraction of texting the stopping distance increases to 17.43 meters. If you were to convert that to feet it would be about 30 extra feet to stop. Now lets say someone was speeding and going 70mph and decided to text. Without texting, the average stopping distance is around 18 meters; however, now add the distraction of texting, the stopping distance increases to around 41 meters. In no way would that ever be safe.
  10. Everyone has those days where they challenge their siblings to a race. But at the end of the competition, how do you know who is the most powerful? During physics class, one of the labs taught us that whoever does the most work in the least amount of time is the most powerful. For example, whoever can run up the stairs the fastest wins the competition. Next time you want to have a friendly competition with your sibling, challenge them and tell them you're the most powerful. According to the definition, power is defined as the rate at which work is done. However the same amount of work can be done with different supplied power if the time is different. But going back to the competition with your sibling...the formula for power is work/time. So the less time someone takes to complete the activity, the more power they have. For example if two people are completing the same amount of work of 20J but person A finishs at 10 seconds and person B finishs at 6 seconds. Person A's power is 2 watts and person B's power is 3.3 watts. Even though person B is only finished in a little bit less time than person A, person B is still more powerful.
  11. wow really cool approach on physics and homework
  12. This was very intersting on how you connected swimming to physics
  13. When someone ends up comitting a crime, sometimes a gun is involved. For example last week on a feild trip, i was able to sit into a trial of someone who commited a murder. During that trial they brought up the evidence that the lady was killed with a gun. When they brought up someone to testify, he was a gun expert. He started talking about how the gun must have been shot and how projectiles are involved. I thought it was cool how someone started to bring physics into trying to solve a murder. Also he started talking about the angle that they must have shot the gun at and how it would make the damage to the person differ. Overall i thought it was very interseting how they used physics in order to figure out if that gun really was the weapon that killed the lady.
  14. Over the course of the srping season I watch my brother play baseball for the school. However a couple of nights ago my family was watching baseball and i realized that alot of physics is in the sport. For example when someone gets up to go and hit the ball, they try to hit it the farthest because they want to be able to run around the bases in order to score. For them to be able to get the ball to go the farthest, they have to hit it at a 45 degree angle. Although they dont always hit it at that angle, sometimes they get pretty close to it. Also in baseball, whenever the ball is thrown to another player or hit into the feild a projectile is created. Depeneding on the angle that the ball is thrown it can either go a long distance or a short distance. If someone was trying to throw the baseball from the outfeild to try and get it to homeplate, they are going to need alot of force in order to get the ball that far of a distance. In conclusion physics is used in the sport of baseball.
  15. Over the course of October, a catapult project was assigned. While my team and I started working on it, i realized alot of physics goes into a catapult. In order to get the catapult to launch the farthest, you want it to shoot at a 45 degree angle. Also when making a catapuly you have to figure out what is the best way to build it so it will be able to shoot the softball the farthest. When building, we decided to make it so that the sides and base were very stable. We figured that by doing this it would allow for the arm to swing fast and not move the sides. Also when making the catapult, i realized that you can use kinematic equations to find out any of the variables. Because the catapult produces a projectile, you can use horizontal and vertical equations to solve and find velocity, distance, time, or acceleration. I think its very interseting that by having just three variables you can solve for any of the five. When launching the catapult, we will have the distance and time and we can make some assumptions for the third variable. So we can find the velocity. Overall i think the catapult was a good way to be able to build something and see how physics is really involved.
  16. i liked how you were able to do something you like and compare it to physics. very well written
  17. hannahz


    very well written, made me look at volleyball in a new way
  18. During physics this week, I have learned many new things when it came to free- fall. I learned that the accerleration on the earth is 9.81cm/s/s. I also learned that the weight of an object doesn't normaly affect the rate at which it falls. For example in the lab we did this week, we dropped a 200g and a 500g weight starting from the desk. Although it looked like the 500g weight fell faster, it was only due to air resistance. I also learned that the slope of a velocity and time graph represents acceraltion. For example, in the lab it showed that slope of the average velocity and time graph represented the acceraltion. Also I learned that in order to solve kinematic equations, you need three of the five variables to solve an equation. There is also a number of kinematic equations that we use in order to find out the variables. The variables inculde, inital velocity, final velocity, distance, accerleration, and time. Using all the equations you can solve for different variables. Overall this week, I expanded my physics knowledge.
  19. hannahz

    About Me

    Hi my name is Hannah. I participate in student council and am a Deca member. I also have one brother and two cats named Sunny and Oreo. I enjoy spending time with my family and love hanging out with friends. I am a junior in high school this year and I love math and science. I love being able to solve word problems and I'm so excited to see what this class will bring. I decided to take physics because it was next in line for my science credits and my counselor suggested it because I have a love for math. I'm excited to see what new things I will learn this year.
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