LSA E Mech 2017-18

Conservation of momentum was demonstrated through the collision of 2 tennis balls.  The tennis balls were set on a track as shown.  One ball at rest and one ball given force to start the motion. It is seen that this is not a perfect example of conservation of momentum.  Lots of momentum and energy was lost in the initial collision when the tennis ball bounced up.  The energy expended in the y direction wasn't reflected in the x direction.  This energy was expended over the course of a few small bounces that were difficult to pinpoint to measure.  Although the ball moved vertically, the vertical displacement was equal to zero at the end of the system. Regarding the conservation of momentum: v1 (initial): 0.9128 m/s v1 (final): 0.2285 m/s v2 (initial): 0 m/s v2 (final): 0.3519 m/s mass of tennis ball: 0.0585kg (equation for elastic collision because trying to find conserved momentum) m1*v1 (initial) + m2*v2 (initial) = m1*v1 (final) + m2*v2 (final

Jump! What would happen is everyone on Earth gathered in a single place and jumped at the same time? This question has repeatedly asked by many people throughout the world. Because of the number of people and assumed greatness of total mass, it seems as though the jump would have some sort of large effect on the Earth. To answer this question, Rhett Allain, an American associate professor of physics at Southeastern Louisiana University and the author of Dot Physics, used estimated numbers and momentum and energy equations. If all 7 billion people on Earth were to gather in a single place, they would take up the space equal to about the size of Rhode Island. The mass of the Earth is about 6*10^24 kg and the gravitational field is constant at about 9.8N/kg. Assuming the average weight of each of these people is about 50 kg and everyone jumps 0.30 m, calculations using momentum and energy can be used to find the effect of this jump on the Earth, as the velocity of t

"What would happen if everyone on earth stood as close to each other as they could and jumped, everyone landing on the ground at the same instant?" The logistics of getting all the people on the Earth in one spot is almost impossible.  So to start this scenario, entire Earth’s population has been magically transported together into one place.  A crowd of all the people in the Earth standing as close together as possible would take up an area the size of Rhode Island. Then, somehow, if everyone jumped and landed all at the exact same time... ...nothing would happen. Earth outweighs the people on it by a factor of over ten trillion. On average, humans can vertically jump maybe half a meter on a good day. Even if the Earth were rigid and responded instantly, it would be pushed down by less than an atom’s width.   Technically, this delivers a lot of energy into the Earth, but it’s spread out over a large enough area that it doesn’t do much.  However, the sou

What would happen if everyone in the world were to go to the same place and jump at the same time? First off, it would be travel hell, with 7 billion people all trying to get to the same place in the world.  Assuming that everyone would be doing this in Rhode Island, they would have to come through TF Green Airport.  That in itself would take many years. Now, if everyone were to jump at the exact same time, nothing would really happen.  When the masses of everyone are added up, it does not even come close to the collective mass of the earth.  Although we have 7 billion people already on the planet as is, we would need much more people to actually have an impact on the earth.  The only thing that would happen if everyone were to jump, is the earth would move a very small amount.  If everyone were to jump in the same place at the same time, everyone would go deaf, as the sound would be 200 decibels.  The force would also cause an earthquake, and if everyone jumped on the coast in a

The common question "What would happen if everyone in the world got together and jumped at once?" has been asked by many physicists and is very popular. To answer this question, we would need to assume that the entire Earth's population was transported to one place. Other assumptions include that there would 7 billion people in that one place with an average weight of 50 kg and an average vertical jump of .3 meters. Also, the mass of earth is 6 x 10 24 kg and force of gravity near the Earth’s surface is 9.8 N. With these assumptions there are not outside forces on the system meaning that both energy and momentum would be conserved in the equation. This means that the initial momentum of the planet plus the initial momentum of the people must equal the final momentum of the planet plus the final momentum of the people. Let’s say that the initial instance is right after the people jump and that the final instance is when the people are at their maximum height. Energy is al

     What would happen if everyone in the world jumped at once? Nothing really. The collected mass of everyone in the world isn't big enough compared to the mass of Earth. If we all jumped at the same time Our force would propel Earth away from us, but not very far at all. Earth would only move away from us 1/100 of the width of a single hydrogen atom. In the end Earth as well as the world's population would return to its original starting places. If we wanted to be able to move Earth we would need several times more people than we have now. If we had that many people we would resemble the strength and power of an earthquake. Some earthquakes have the power to redistribute mass such as the one that took place in Japan, 2011. That earthquake was so powerful that it moved a lot of mass towards Earth's center that every day since has been .0000018 seconds shorter. Not a great change but it's still a change.      But say if you jumped at a certain location such as T.F. Gr

There are 7.6 billion people in the world. If everyoen gathered together at one place at one time and all jumped together, what woul happen to the Earth?  Simply put, even if everyone on the planet jumped at the exact same time the eath would be virtually uneffected. This is becasue teh mass of the earth is approximately 5.972 * 10^624 kg and if you were to calculate the mass of all humans put together it would not come near that number.  Conservation of momentum: p1i + p2i = p1f + p2f m1v1+m2v2=m1v1f+m2v2f Numbers: Human population as of December 2017= 7.6 billion Mass of the Earth= 5.972 * 1-^24 kg Average human mass=136 lb/62kg Average vertical jump=0.5 m In the equations, 1 represents the Earth and 2 represents the people.  In this situation the equation is elastic becuase the Eaerth is in the system and momentum is always conserved. 1/2m1v1^2+1/2m2v2^2=mgh  --> h initial = 0 1/2m1v1^2+1/2m2v2^2=0 1/2m1v1^2=-1/2m2v2^2 m1v1=-m2v2 v1=-m2

What if everybody in the world jumped at the same time at the same location?  It is practically impossible for all people to be in the same location at the same time (mainly because there are 7.6 billion of us).  Although one may think that the mass of all the people in the world combined may be a lot (which it is), it is nowhere close to the mass of the world.  Due to the major difference in masses, everybody jumping at the same time would have no affect on the world at all. Values that I used: Amount of people of the world: 7.6x10^9 Average mass of a person: 70kg Average vertical jump of a person: .5m Mass of the Earth: 5.972 x 10^24 kg An elastic equation will be used because momentum is conserved, which means kinetic energy is also conserved.  The equation that I used is the conservation of momentum equation. m1v1+m2v2=m1v1f+m2v2f To solve for the velocity of the earth I used a conservation of energy equation.  H in this equation is equal to zero because the Earth did n

What if everyone in the world gathered at TF. Green Airport and jumped at the same time? First off, this wouldn't be possible as a crowd this size would take up the entire state of Rhode Island. Second off, TF Green would have to function at 500% capacity for years in order to transport everyone to Rhode Island. However, if everyone managed to get to Rhode Island the force of the jump wouldn't affect the earth at all. This is because the Earth outweighs all the world's humans by a factor of over ten trillion. Even with the average human vertical of half a meter, the Earth would only move by less than an atom's width if it were completely rigid and the collision was perfectly elastic. When people's feet hit the ground it delivers a lot of energy into the Earth but then it is spread out over a large area so there is no serious change. However, the sound of feet hitting the Earth would create a deafening roar that would last a few seconds.  This sound could shatter

To perfectly demonstrate conservation of momentum, my group decided to utilize exercise balls we had at our house. The medicine ball had a mass of 4 kg and the volleyball had a mass of .281 kg.  In our experiment, we had the volleyball rest on the patio 1 meter in front of the medicine ball. While the volleyball was at rest, my sister gave the medicine ball a healthy push and let physics do its thing. Using Vernier Logger Pro, I recorded the video, analyzing it to show the conservation of momentum between this collision Collisions between objects are governed by laws of momentum and energy. When a collision occurs in an isolated system, the total momentum of the system of objects is conserved. Provided that there are no net external forces acting upon the objects, the momentum of all objects before the collision equals the momentum of all objects after the collision. If there are only two objects involved in the collision, then the momentum lost by one object equals the momentum gai

Hypothetical and far out questions are what create great physicists and allow for us to discover and test things that have never been thought of before. Even as kids, we let our minds wander and ask questions that we never knew could be proved or disproved by physics. One question that I, as a young questioning child, and many other highly regarded physicists ask is simple; what would happen if every single person got together and jumped at once? This situation is completely unlikely to ever happen, so the only way we could ever know what would happen is through physics. Okay, so lets set the scene. Everyone, all 7 billion people, could fit into an area the size of Rhode Island, so lets assume that everyone did  travel to the smallest state in the US.  Finally, in unison, all 7 billion people jump. The push against the earth doesn't affect the earth at all, considering the Earth outweighs everyone by a factor of a mere 10 trillion. Even if the Earth were rigid and responded ins

If the whole population jumped at once, nothing amazing would happen. The Earth would be completely fine. The Earth would continue to rotate on its axis at 1,000 mph and we would still continue to rotate around the Sun at 67,000 mph. If all the people on the Earth jumped at once at one central location, it would not be nearly enough force to knock the Earth off its orbit or disrupt its rotation on its axis.  Our collective mass is an awful lot—just not compared to the mass of the Earth. However, some other interesting things might happen. For example, if everyone on the Earth decided to come to T.F. Green Airport and jump at once, there would be a loud bang at an astounding 200 decibels.    For context, a jet engine produces 150 decibels of sound at takeoff, and our pain threshold is at 120 decibels In addition, since T.F. Green is near the coast, there is a change that there could be a tsunami. There would more than likely be a large scale upper-crust earthquake.  The gro

Over break, I spent my snow day learning the physics behind the game pool. I did this by analyzing the collision of two pool balls. I analyzed the collision by setting up two pool balls in the background to mark one metter. Then my dad recorded me applying a force to the first ball to hit the second ball at rest propelling it. By doing this I was transferring momentum and initiating some movement in the second ball while the first one came to a stop. I then put the video into logger pro. First I used the two balls I set up in the background that measure 1 meter and used that distance to scale. Then I started to collect my points from the yellow ball, the one that was hit (mass 2). I used Logger pro to collect the velocity of the second pool ball throughout the collision. This graph shows the velocity of the second ball in the x direction.  *The second ball reaches 0.486 m/s after being struck by the first ball* This graph shows the x velocity of the First ball b

For the Snow Day blog, I decided to bring out the old Nerf guns to calculate the momentum caused by the bullet on an object.  The link below brings you to the video clip of an inelastic collision between a bullet from the Nerf Mega Centurion and a paper bag. https://drive.google.com/file/d/0B8TxV_jfPW7lWlV5NWxmamFrNzJRTnh1bTdiT3ktZ1ZKaURN/view (Unfortunately I could not upload the video so I instead made a link that can be used to access it) The mass of the bullet is 0.0025kg and had an initial velocity of 8.47 m/s.  The paper bag had a mass of 0.068kg and an initial velocity of 0.  The velocity of the bullet was found by using the Logger Pro Program with a Distance vs. Time graph.  Using all of the given information that I had achieved, I used the formula for inelastic collisions to calculate final velocity of the two masses combined. Equation Formula: m1v1+m2v2=(m1+m2)vf Plugged in Values: (.0025)(8.47)+(.068)(0)=(.0705)vf .0212/.0705=vf vf=0.301m/s The final veloc

What would happen if everyone on Earth, all 7,442,000,000 of us, were to jump at the same time? If we all jumped where we are right now, nothing would happen. The population of Earth is pretty even distributed, so all of the individual jumps would cancel out. Let's say we got everyone on Earth to gather in one spot. Everyone could live, fairly comfortably, if we packed into an area the size of Texas. However, I imagine we would want to fit everyone into the smallest area possible. Unfortunately, all seven billion people would be unable to stand next to one another in T.F. Green Airport, but they could all fit shoulder-to-shoulder in the 503 square miles of Los Angeles. Although it would be impossible for this to happen, let's imagine that ever yone took time out of their day to squeeze into L.A. If everyone jumped 30 centimeters in the air at exactly the same time,  the Earth would be pushed away about 1/100th the width of a Hydrogen atom. To put this into perspective, a pi

EVERYONE JUMP Earlier, we were posed with the question "What would happen if everyone jumped at the same time?". Would this have an affect on a mass as large as the Earth. Although it seems that everyone jumping at the same time would cause some sort of impact, the most impact that is produced of this event would be the sound of 7 billion people jumping. It seems reasonable to assume that the earth would more slightly, but the recoil speed of the earth would be very miniscule. No one would even realize that the Earth moved the amount of one atom. This is because the Earth is heavier than all the people who inhabit it by over 10 trillion. Once everyone realizes that this silly experiment amounted to nothing, there would be a major problem. How would everyone be able to make it back to their hometowns. If everyone is in Rhode Island, it would take extremely long to move people back.  T.F. Green is not the largest airport by any means. This airport can handle a few t

Nikki Nappi Period E What is everyone in the world jumped at once? https://what-if.xkcd.com/8/ http://mentalfloss.com/article/54836/what-would-happen-if-everyone-jumped-once In the scenario posed by this "What if" website, everyone in the world would stand as close as they could to one another. In this proposed scenario, the crowd is the size of the entire state of Rhode Island. At noon, everyone jumps. This does not affect the Earth since the Earth outweighs the entire population by about 10 trillion. Humans can really only jump about half a meter high, so the Earth would only really move about half an atom.The increase of mass to the center of the Earth would increase the rate of rotation. Huge earthquakes only increase the earths rotation by 100,000ths of a second. However, the current population of the earth would need to increase by seven million times what it is now to even make that much of a difference. The collective mass of the population of the world

For the snow day blog, I decided to test two different types of inelastic collisions with snowballs. The first video demonstrates an inelastic collision in which a snowball of 0.25kg hits a wall. In this inelastic collision, the 0.25kg snowball travels at 1.8m/s and impacts the wall. The snowball breaks into pieces and transfers 0.45 kg*m/s to the wall which is not noticeably moved(high quality wall, cedar shingles, can't beat it). This second video demonstrates a similar collision in which another 0.25kg snowball hits a stick and knocks the stick off of two cones. This screenshot shows the trajectory of the snowball and stick as the kinetic energy is transferred from the former to the latter. If we use the momentum formula of m1v1+m2v2=m1v1f+m2v2f we can calculate the mass of the stick that was hit based on this data and then draw conclusions about energy loss. The data shows that the snowball being thrown had a velocity of 1.8m/s and the stick after

WHAT WOULD HAPPEN IF EVERYONE JUMPED?? If everyone in the world (7.6 billion people) gathered in one place and all jumped at the same time, what would happen to the Earth? Would it be effected?  This is a question that scientists have been asking for years. The answer simply put is that even if everyone in the world jumped at once, the Earth would virtually be unaffected. This is because the mass of the earth is approximately 5.972 x 10^24 kg, and all human mass put together would not even come close to that number. To see the exact number of how the Earth would be effected, I used the conservation of momentum equation.  p1i + p2i = p1f + p2f m1v1+m2v2=m1v1f+m2v2f I know that in this situation the equation is elastic because the Earth is in the system and momentum is always conserved. In all my calculations, 1 will represent the Earth and 2 will represent the people.  First here are the numbers I used for the data: Average human mass = 136 lbs / 62 kg (<https

What would happen if everyone jumped at once? The current human population on Earth is estimated to be about 7.6 billion people. The global average body mass for a human is 62kg (it sounds small because in America our average is 80.7kg, about 180 pounds). The humans will be jumping, giving themselves potential energy mgh at their max height (about 0.5 meters for this analysis) and then that kinetic energy will be converted to kinetic energy that will be involved in the collision that hits the Earth. If a 62kg person accelerates toward the Earth at 9.8m/s^2 for 0.5 meters, mgh can be used to calculate the KE on impact. m1 is the mass of all of the humans on Earth. This can be estimated to 7.6B*62= 471,200,000,000kg. If you assume that all of the humans on Earth jump 0.5 meters and use mgh to calculate the KE, then 235,600,000,000J=KE. 235.6GJ is an immense amount of energy, but this energy is facing a mass of 5.972 × 10^24 kg.  If you consider "everyone jumping at once"

     This past snow day, the class was tasked with finding scenarios where conservation of momentum occurred and to show the kinetic energy that was lost. Stumped at first about what I could do to show conservation of momentum, I finally decided to do a collision of two objects with one being at rest. The two objects I chose were soccer balls.  Both of the soccer balls weighed .435 kg. The initial velocity of the first soccer ball was 2.08 m/s. X-Velocity         The second soccer ball weighed the same as the first. After being hit with the first soccer ball the final velocity for the second soccer ball was 1.38 m/s. X-Velocity  Equations:  P=mv=(.435)(2.08)= .904 kg m/s --> First soccer ball  P=mv=(.435)(1.38)= .625 kg m/s --> Second soccer ball  First soccer ball: 1/2(.435)(2.08)^2=1/2(.435)(0)^2 --> .941 J lost  Second soccer ball: 1/2(.435)(0)^2=1/2(.435)(1.38)^2 --> .431 J gained        Although the data sh