If a tree falls in the forest, and no one is around to hear it, does it make a sound?
When a ball hits the ground or an axe hits a tree, we can hear a noise signaling this collision. Obviously, sound waves are produced, but where exactly do they come from?
When two objects collide, one of two things can happen: an elastic or inelastic collision. In the case of elastic, no kinetic energy is lost. Inelastic, however, involves a loss of kinetic energy. Where does it go?
Part of it g
I was wondering how a credit card (without a chip) might be able to store the data needed to make a purchase, so I decided to look it up. As with most things, it actually is related to physics.
I knew that the strip was a "magnet", but in reality, it's several magnets (by several I mean a lot) that are polarized with north and south on differing sides. The strip stores the data you need with these magnets. There are three separate tracks on the magnetic strip that all store different inform
Makeup is one of my biggest interests, however I wake up late a lot of the time and don't have time to put it on. It's fun to be creative and almost create art on your face, and to show it off for a day.
The big physics principle behind makeup is trying to combat the force of gravity and using friction to help the makeup apply.
All the makeup on your face is applied with some amount of friction helping you out. Whether you're applying lipstick from the tube or using a brush to put on
This is vaguely about physics but hey it's still related to physics. I wore my physics hat (thanks Mr. Fullerton) to a student council conference. I had a few friends joke about it on the ride there (calling me a nerd as your friends do). When we got to the retreat, however, it was actually cool how a few people I talked to asked me about the hat. They asked if I was taking physics and if I wanted to major in it (yes and yes), and I ended up having a cool conversation with a girl about particle
There are two types of colors in the world: additive and subtractive.
Additive deals with the source: sun, stars, and light bulbs for example. These light sources mix red, green and blue wavelengths to produce white light. If you were to spotlights that slightly overlap one another of those three colors, where all three overlap would create white light.
Subtractive deals with objects that reflect light, so anything that isn't a light source itself. Consider your favorite shirt. Mine
I'm not talking about cannonballs like what you shoot out of a cannon. That's obvious, a huge object is hitting you at a large velocity therefore there's a huge force transferred to your body.
I'm talking about the cannonballs you do when you jump into the pool with your friends on a warm summer day. (Which we're all looking forward to after this winter).
When you jump into a pool, the water has some amount of surface tension to oppose objects from entering it. When you dive in with
There are several ways in which cars demonstrate physics. For one, when you turn, hit the gas or brake, you can see the property of mass called inertia. Anybody or anything in the car tends to continue traveling in the direction the car was originally going in or stay still if the car was stopped.
Also, the physics behind tires show how cars move. As the tire spins, it uses the friction between it and the road to push the car forward. This is why in snow or mud, where there is little fricti
I'm sure several of us have ran around the house with socks on and tried to slide on wood or smooth floors.
Using what we know about friction, we can see that the equation is the coefficient of friction times the normal force, or mg. Since we are on earth, there is obviously a force from gravity and a person has mass. Therefore, the explanation for this fun trick must lie in the coefficient of friction. Since you can slide a decent distance, the coefficient must be small, therefore causing
I work at the bar, Murph's, on Friday and Saturday, and one of my tasks is to refill ketchup bottles. In order to get the ketchup to the neck of the bottle, I hold it by the bottom and spin it in a vertical circle.
This works because of centripetal force. You might be saying, however, that centripetal force pulls objects towards the center of the circle. While this is true, it acts on less dense materials at a greater magnitude. Inside the ketchup bottle, there is only air and ketchup. Sin
My bird, Tucker, has a swing in his cage, and the way it is hung up makes it act like a pendulum. The length of the swing is 15 cm, or .15 m, and since it is obviously on Earth, the acceleration due to gravity is 9.8 m/s^2. This allows me to use the equation for period of a pendulum. This gave me an answer of .777 seconds.
The only issue with this is that there is friction between the cage and the swing. This causes the swing to slow down and come to a stop eventually.
Last night, I went out and saw the movie Split. I was slightly intrigued by the reviews, and it was said to have a really surprising ending, so I put aside some of my personal opinions on the topic of choice and watched it.
It was a very interesting movie to say the least, and if you're planning on watching the movie, I would stop reading here, because in order to get into some physics I have to spoil the ending, which is entirely the best part.
Okay, now that you're sure you want to
Personally, I don't like fishing and I believe that if you aren't going to eat the fish it's cruel, but I was playing Stardew Valley and I had been doing a lot of fishing when I started thinking about the physics of fishing.
If a fish is on the hook, you start to reel in the line. As you do this, you created tension in the line. If the fish is able to produce a larger force in the opposite direction of this tension, the line will unroll a bit more. However, if the tension in the line is cre
Hanging a picture can actually show a lot of physics dealing with force and friction.
First, you have to hit the nail with a hammer into the wall. Each time you hit the nail, you have to overcome the force of friction between the wall and the nail to get it to go in further. The hammer rebounds back after hitting the nail and you feel the force in your hand.
Then, depending on how heavy the picture you hang is, the wall has to exert a force equal to m*g on the nail to overcome the com
One equation in physics is torque, which is the Force applied to object to rotate it about an axis times the radius the force is applied at. Torque only takes into account the force perpendicular to a surface, because any other direction will not cause it to spin.
When you open up a laptop, either with a force at some angle or directly perpendicular, the force acting perpendicular causes a net torque and spins it about the axis.
The same can be seen on doors, and even books. Also, some
I had an incredibly weird dream the other night. I was driving with my mother and in front of us was a man on roller blades using two machine guns taped to his arms to propel himself forwards.
I was about to forget my dream all together until I started thinking if physics would allow such a thing to happen.
Similar to the way a rifle would recoil when a bullet is shot, the machine guns would recoil when the bullets are shot out of them. Normally, they are anchored to something so the r
I used to wonder why the pendulum in a grandfather clock was there, and I originally thought it was for purely visual interest.
Now, I realize that the pendulum acts as a pendulum to keep the clock working at exactly the right time. The pendulum has a period of 1 second and each time it swings left or right, it moves the clock through one second.
But what length should the pendulum be in order to keep time at 1 second?
The equation for the period of a pendulum is T = (2* pi) (L/g)
One of my more recent favorite games has been Stardew Valley. It is essentially an updated version of the game Harvest Moon, which originally came out in 1997 on the Gameboy, which is what I originally played it on. It is a game where you inherit a farm from a dying relative, and you come to find it overrun with weeds, trees and rocks. You slowly clear it out, plant crops and adopt animals. You can also mine and fish, and you slowly build relationships with the people in the town by joining them
One comment I received on a previous blog about backpacks was about a backpack literally breaking your back. I decided to do some research on the topic. It appears that a vertebrae in your spine can withstand about 500 lbs of force, which is about 2225 N of force. In order to do some damage to your spine, you would need to have a backpack weigh this much in newtons. This means that your backpack would have to have a mass of 227 kg, or almost 500 lbs to do real damage to your back.
To put t
In the winter time it seems that everyone is shocking each other. I shock myself on every chair at school, I swear. The worst feeling however, is when I shock my cat. Most of the time it happens when I'm petting her.
The reason why is that when I pet her, I am picking up electrons from her. This gives her a net positive charge and myself a net negative charge. I don't know the magnitude of the charges but we would have equal and opposite charges, assuming I am not grounded and my body conta
For my birthday, I received the video game called Firewatch. You play as a man who went through some rough points in his life, and so you take a job as a forest fire watchman, and you do a little bit more for your boss, Delilah. As you explore your area of the woods, you climb up and down several rock walls using only a rope, and the ropes have been sitting out in the forest for at least three years. I have only seen the character once, and he appears to be about 250 pounds, or roughly 113 kg. I
I carry all of my school supplies around in my backpack at all times, and it gets pretty heavy at times. I have a binder for all 4 APs, 2 folders, 3 various notebooks, and other odds and ends to get me through the school day. After some light research, I found the average binder weighs 3 pounds, and since my notebooks have the same amount of paper, I'll assume they'll have the same mass. 3 pounds is 1.36 kilograms, and since the other odds and ends probably are around 5 pounds, I converted it to
I am ridiculously addicted to french fries. I don't have a specific favorite place or type of fry that is the best, literally any fried rectangular potato will do for me.
I ate some french fries today, and figured why not address the physics behind me chewing my fries. You produce a different amount of force with your molars than your incisors. Men produce about 150 pounds of force with their molars and 83 with their incisors. Females can produce 108 pounds of force with their molars and 57
If you haven't noticed, I really love my kitten. I am proud to call myself a crazy cat lady in training, but lets not go to far into me, we're here for physics! And I already wrote an all about me.
Kittens jump around and run alot. I'm going to track my cats movement for 7 minutes (I like the number 7 so that's why I picked that) and talk about the general physics in her energy.
12:48 - Mia is standing on the ground at first. She then jumps onto my bed, increasing her potential energy.
As you would know if you have a kitten, they only get worse as they age. This is intensely true for my kitten, Mia. Not only does she constantly escape her room, but she has figured out that my computer screen is touch screen, and wreaks havoc on whatever I am doing on the internet by touching it.
I often have to pick her up to try to prevent her from destroying something. She only weighs two pounds, even though she is 13-14 weeks old. I don't have to do much work because of her size, but
I didn't realize we could write about ourselves until recently, so I'm gonna join the party and introduce myself. My name is Alaina, and I am a senior this year. I hope to major in Physics and Math in college next year, and honestly I'd like to go to University at Buffalo even though I'm applying to Ivy League schools. I work at Murph's Irondequoit Pub every Friday, and they really do have the best wings in town, but also the best bread. I'm addicted to it. I love cats, and right now we have fou
The pages of APlusPhysics.com, Physics in Action podcasts, and other online media at this site are made available as a service to physics students, instructors, and others. Their use is encouraged and is free of charge. Teachers who wish to use materials either in a classroom demonstration format or as part of an interactive activity/lesson are granted permission (and encouraged) to do so. Linking to information on this site is allowed and encouraged, but content from APlusPhysics may not be made available elsewhere on the Internet without the author's written permission.
APlusPhysics.com, Silly Beagle Productions and Physics In Action materials are copyright protected and the author restricts their use to online usage through a live internet connection. Any downloading of files to other storage devices (hard drives, web servers, school servers, CDs, etc.) with the exception of Physics In Action podcast episodes is prohibited. The use of images, text and animations in other projects (including non-profit endeavors) is also prohibited. Requests for permission to use such material on other projects may be submitted in writing to firstname.lastname@example.org. Licensing of the content of APlusPhysics.com for other uses may be considered in the future.