A human body has the ability to release a huge amount of strength through its muscles. The reason that a person is unable to unlock all of this strength at any given time is so that muscles do not get strained or torn in the process. This is a cool safety feature of the body so that people do not over exert themselves and end up crashing. In order to produce large amounts of strength it takes a lot of energy and using muscles to their max for a long period of time can be very harmful to the body. However, in some cases when on an adrenaline rush people are able to tap into this strength in order to do things that seem to be humanly impossible. There have been incidents were people have lifted cars or moved heavy objects in order to save or do something. This shows just goes to shows how powerful the human body is.
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So I recently came a crossed an article that said drinking warm liquids on hot days will actually cool you down faster than a cold drink. I found this really strange because I would have thought that a nice and cold refreshing drink would cool you down,however, like normal I was wrong. I thought that was really interesting so i decided to look into it. I found out that this is actually true. When drinking a hot liquid on a hot day it will cause you to sweat more than than usual, cooling you down. This is cool because with sweat being a natural cool down for the body it is cool how you can manipulate your body temperature so that you can do it more. Drinking a warm drink consistently allows you to produce about a 100 ml more sweat than if you were to drink a cold drink(A warm drink being 50 degrees Celsius and a cool drink being about 1.5 degrees Celsius) So if it a hot day and really want to cool down i suggest that you go grab some nice and hot tea even though a cold glass of water would sound better (which I will probably still drink on a hot day)
It is better to not get hit in the head but sometimes it just ends up that way. Hockey helmets are designed like most helmets with the ability to absorb most of the energy from impact. The thing that I believe separates a hockey helmet from a standard football helmet is the fact that the top of the line hockey helmet rotates a little around your head without jerking your head in the initial impact. (I don't Know enough about football equipment to speak on behalf of the equipment) However, most injuries that occur to the head are caused from the initial jerk of the head when the brain remains still for a moment while the head moves. As this movement happens it yanks on blood vessels and nerves causing strain on the head and if bad enough an actual brain bleed or a concussion. This is why I wear the top of the line helmet now because previously having a really bad concussion and now I must wear it to prevent future ones. With this helmet no one is safe from every hit but with the ability to rotate a little around your head it gives you a slight edge over other helmets.
When an explosive goes off under water the shock wave carries a lot further than it would if it were on land and in the air. This is cool because water has a higher density than air so this mean that it is harder to move or has higher inertia. And we know that inertia is a measure of how restive something is to acceleration. This means that after the explosion goes off the shock wave from that will carry further through the water with smaller deceleration. From this we know that this shock wave will be carried without losing speed and keeping it's high kinetic energy. As a result of this if you are anywhere near an explosion in the water you will be feeling most of the energy from the explosion. This energy from the explosion depending on the size could have enough energy to shatter every bone in your body. I would suggest getting out of the water if you were in this situation but, chances are you would be to late.
When a person is jumping from a high distances to the ground or other hard surfaces it is important to maximizes the time that you are decelerating. This is vitally important because the thing that causes injury is the force that is applied to you over short periods of time. If you can spread the force out along a period of time the impulse over time wont be a as big thus your body will not have to absorb all of the energy at once allowing for a safe landing. This also allows for the body to be able to absorb greater forces. One way to increase the time to stop is by bending the knees. This is very important because if you don't you will feel the force all through your body
Everyone calls it bullet proof glass but in reality nothing is bullet proof. The term for it is bullet resistant because if something is shot enough, one will find its way through eventually. Bullet resistance glass is a combination between very thin sheets of glass and even thinner sheets of tough plastic made of polycarbonate. This is able to work because as the bullet hits the glass it breaks the thin sheets of glass and the energy from the bullet is absorbed by the plastic layers. To make this effective you increase the number of layers to absorb more energy. The ratio between glass to plastic is normal 3:1 were the layers of plastic are 1-3 mm thick and the glass is 3-10 mm thick. This is crazy to think that by layering glass and plastic it is able to stop a .308 caliber marine sniper bullet, one that will knock you off your feet entirely. In this video you can see that this glass is only successful for two shots from a .308 rifle at close range. So if you are in a car with a sniper shooting at you and have this glass between you and the bullet, I would suggest driving pretty fast.
Kronwall is one of my favorite defenseman in the NHL. The reason for this being his huge hits that he has (shown below) and this great defensive play. The reason for hit great hits is because he combines his massive self with a good amount of speed to completely wreck players. The main reason this is so effective is because of a fundamental aspect of physics which is the idea that momentum must be conserved. Since he catches his opponent off guard it allows him to build speed and use his mass to collide with the other played and cause for him to continue on in his original direction. Even though his speed gets slowed significantly from this it is because he has just collided with another massive player. But, since he has more speed and a better center of mass this opponent gets "Kronwalled"
So last night it was very late and dark and my mom decided to leave a basket at the top of the stairs. I think you can see where this is going from the title. So going down stairs was very fast. And getting up the only thing that I could think about is what just happened in terms of energy. The first thought that I had was how much potential energy I had at the top of the stairs. The next was how much transferred into kinetic energy from falling down the stairs. Then I thought about the mid way point where I had kinetic energy, potential energy and a little rotational energy. I found this funny because physics changes the way you think, you can be sitting on your butt at the bottom of the stairs and still be thinking about how it relates to physics and then realize you have an EM exam on Friday!
When you are walking in the snow have you ever noticed that when your foot lands in light, fluffy snow your footprint is actually bigger than it is and you can see the extra space with your foot still there? This happens because when you are bringing your foot down it traps a pocket of air between your foot and the ground. As a result of this once your foot hits the ground that air pocket is dispersed thus it causes for the snow around your foot to move even though you are not touching it. This can be pretty satisfying when you are walking home in the freezing cold with nothing to do.
With this wonderful weather comes wonderful roads. From driving, it can be a very dangerous with the coefficient of friction much smaller making roads very slippery. Thinking about our previous unit with rotational and transnational motion it can relate a lot with a car in the snow. When starting up the tires often spin when very slick out causing for more rotational movement rather then the wanted transnational. And then as you get going you begin to build more transnational rather than rotational. So for every one out there driving be careful!!!
Why does a pencil or any linear object look like it is bending when you wiggle it? I was very curious of this today and was wondering why? The answer to this question is that in the way you are wiggling it you are rotating around its center in such a way that our eyes perceive that the ends of the pencil is moving faster even though the angular velocity is truly the same through out because it is truly a rigid object. The reason for this is because when an eye is viewing a fast-moving object the formed image can be modeled as the image of points that appear to have different velocities on the same object. The reason our eyes do this is the same as when transitioning front light to dark. It takes time for our eyes to focus and adjust to our surroundings so by our eyes focusing on the fulcrum or our fingers in this case, it cases it ends to blur.
So with the hockey season starting today I thought that i would do a blog about hockey. Thinking about skating in hockey and why you need to get your skates sharpened, this is to allow for there to be enough friction to propel you forward. This is just like running were you need friction between the ground and your feet to be able to drive forward by pushing back. The only difference is that in hockey you need the skates sharp to cut into the ice in order to drive yourself forward. This is showing Newtons law where if there is a force in one direction there must be one in the equal and opposite direction. Being able to gain traction is hockey is key to being able to be fast that's why you angle your blades on the ice instead of straight on as you can see in the video below. You can also see how the players you there sticks to go into the turn to help get around the turn more compact instead of having it out wide which would slow you down.
So in the past month I have recently had Knew surgery to remove a torn meniscus. This surgery was relatively quick only lasting about an hour. Knee surgery has come a long way from where it use to be. They use to have to open up the whole knee but now you only walk out with three little holes in your leg. All the thanks goes to physics and the ability to manipulate things using modern knowledge of optics and modern technology. During this surgery they were able to take out a torn piece of meniscus with a viewing tool, a small scalpel, and water to flush it all out. This makes the surgery relatively easy and allows you to walk a day or so after and be back playing sports within two weeks. I am very thankful for physics for it got me back to hockey before the season began.
So my Friend Timmy C. is not the best driver. See he has just stated and doesn't quite get that you cant hit the brakes really hard. So as you can imagine it is a very jerky car ride. And thinking more about this it is because of out mass that we will continue to move forward even though the car has slowed. This is because of inertia and mass is a property of inertia. Inertia is the resistance to acceleration based on mass. So therefore a heavier mass will be harder to accelerate and a lighter mass will be easy to accelerate. Applying this to the car situation above it is easy to understand why we continue to move forward the driver applies the brakes hard because you do not want to decelerate, having mass, so you continue to move forward. Here is an extreme example, caution this clip may be violent in some eyes.
Today in class a cool thought was brought to my attention. The idea that an object that is an infinite distance away from all other objects will have no gravitational potential energy. Its a cool idea because if you think about any object on earth it has its own gravitational field due to the fact that all matter has mass. The earth is a great example of this because we can clearly see the moon and how it travels around the earth which is due to the gravitational pull by the earth on the moon. So thinking of the moon an infinite distance away from the earth than there would be no force acting on it saying that the only planets we are taking into consideration are those in this galaxy. It's weird to think this way with things at an unreachable distance becasue they are not possible and hard to wrap the mind around.
Thinking about what we have been learning in physics, on the topic of energy, it makes it more clear to see some of the physics that goes into taking a shot in hockey. I mean they go so fast but getting there was a little hard for me until this unite that we are in now. Looking at elastic potential energy you can clearly see that in the picture below. It's crazy to see how that potential energy is turned into kinetic energy in fractions of a second and the puck is sent flying at ridiculous speeds.
So this weekend my brother had a hockey game that I went to go watch. I traveled all the way to buffalo to watch his team get beat 5-2. Anyways, during his game he got absolutely destroyed at center ice. It sounds like it would really hurt but getting hit in the center of the ice isn't as bad as it sounds, getting hit against the boards it way worse which I know from experience (I have had my fair share of getting hit myself). But, this got me thinking of why it hurts more getting hit against the boards rather then at center ice. It looks as if it would hurt more getting hit at center ice but it actually doesn't thinking about force over a given period of time. Getting hit center ice means that the force that you get hit with is carried out over a longer period of time rather then against the boards meaning you will feel the force against the boards more because it is carried out over less time. Below are some examples of why it seems lik getting hit open ice would hurt more than at open ice.
A world without friction. That would be something wouldn't it? I cant think of something more hated and loved at the same time more than Friction. I started thinking about this at soccer practice the other day when it was raining out. I kicked a ball on the ground with spin on it but instead of curving it spun going in a straight line sliding a crossed the wet turf. With the coefficient of friction being lower on a wet surface this caused for less friction between the ground and ball causing it to not to curve the way i wanted it to but instead momentum carried it in a straight line. Going back to friction being loved and hated on the topic of a race car, I think this is where it is seen most. Without friction a car wouldn't be able to go forward and thus they need that friction if they want to go anywhere. BUT, then again they are also always fighting against friction trying to get their cars to go even fastest than they already do with things like bearings and probably the biggest air resistance. So thinking about Friction, we only like it was it works for us, not against us.
So last Friday our class of 22 had the pleasure of taking part in a Projectile Lab in which we would shoot our grade. In this lab we would be trying to hit a textbook after making various calculations. Another important aspect of this lab was the fact that if we hit this book the whole class would pass and if we missed the whole class would fail. As many of you know this lab didn't go so hot, crunched for time and lack of communication lead to a complete miss. Mr. Fullerton, being the wonderful man that he is, allowed us to re-due the calculation and write about it in the blog I'm currently writing to receive full credit after that humiliating miss. After doing the calculation again, I came to the conclusion that the book should have been placed at the center of about 2 meters. The thing that messed the class up the most was the fact that there was a lack of time and the push at the end caused for a mix up with numbers due to not being able to think clearly stressed about the time.
After doing this lab and looking back on it, with some more communication it would have helped to make the lab go quicker so we aren't crunched for time also another idea would be to split into into small groups to get an answer which to then compare later instead of trying to work on it as a bigger group. I think that these things are key to this lab to allow for success.
Bellow are my calculations for the value in which the location of the book should have been placed.
I'm really looking forward to this year in physics C. I really enjoyed AP physics last year and it sounds like this year we will be adding onto content that we previously learned which will be great. However, the class so far has seemed pretty terrifying, even though we have only been at it for about 6 days, the thousands of accounts to sign up for and the mountains of work hanging over our heads(which of course has potential to do damage hahaha) makes it look like we are in for a challenging year. But, I do think that with some strict time management and and staying on top of the work it will help to make it easier as we endeavor into the world of physics C.