Wednesday, September 25, 2013
Week 5, Due Sunday, September 29th by 11:00 pm
Some students are still having trouble distinguishing between distance vs displacement and speed vs velocity. So, for this week's blog I want you to tell me how they are similar to each other and how they are different. You can choose to compare and contrast either distance and displacement OR speed and velocity. You do not have to do both. Also, whichever concept you choose to discuss, give me a real world example. Your example must be original and not a copy of someone else's post. If you have any questions, please let me know before Sunday night. Remember, you post an ORIGINAL comment plus a REPLY to another person's comment. If you have trouble posting on the blog, you can send me an email through the district website, physicswithego@gmail.com, on twitter @EgoIsAwesome, or on edmodo.com. Happy Blogging!
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Distance is a scalar quantity that measures the total length or space an object has traveled without respect to its initial position. Displacement, however, is a vector quantity that measures the distance an object has moved from its initial position with an assigned direction, either positive or negative. One real world example could be the cartography of a map, as the scale in the legend will help you determine the displacement between two cities, yet it can also be used to determine the actual distance one must travel using roads to get to another city.
ReplyDeleteI like your example Edgar of how a legend can give you the displacement of two cities and can determine the distance of the two cities
DeleteYou could also use a race car track in order to understand it. But it seems you understand the concept. Good job Edgar!
DeleteSpeed is the absolute value of velocity, in other words, it is always positive. Speed has no direction. On the other hand, velocity does have direction; it can either be positive or negative. A real word example could be in an oval-shaped racetrack, where speed is measured. A real world example that has velocity as the unit of measurement could be in the weather report of a hurricane. Hurricanes travel in certain directions, therefore they are measured in terms of velocity.
ReplyDeleteTrue, however, speed does not incorporate the displacement aspect in its calculation, yet velocity does incorporate the displacement aspect in its calculation.
DeleteYes Edgar, like you stated before, displacement is a vector, or has as a direction, which speed does not have. That being said, I also said speed has no direction, so we're basically saying the same thing. Speed is the change in distance over time, while velocity is the displacement over time.
DeleteYes, but the word velocity insinuates the incorporation of displacement, so even if you used the absolute value of the displacement, you may not have the same result because speed uses total length of travel. For example, if you traveled north 50 meters per second for 2 seconds, then south 30 meters per second for 2 seconds, your average speed by your definition would be 10 meters per second, instead of 40 meters per second.
DeleteSee, you are referring to the average velocity. In that case, you are right, and it would vary, but I was not referring to the avg. velocity or speed. If we travel south for 100mi over 2hrs, the velocity is -50mi/hr. The speed, or the absolute value of velocity, would then be 50mi/hr.
DeleteDistance is scalar value of how far an object traveled regardless of direction. Displacement is the vector value of how far a object has been displaced, meaning how far is it from where it started for where it ended.
ReplyDeleteA real life example of displacement would be a plane trip from Houston to London, the displacement would not be the same as the distance.
DeleteSpeed is the rate of change of motion meanwhile velocity is speed with respect to direction. A speedometer shoes the speed of a vehicle. A hurricane can be an example of velocity when measuring the winds of it.
ReplyDeleteTrue, but you could elaborate more by saying that in order to find the velocity of the winds, you have to find the direction in which it is going, like north, south, east, or west.
DeleteI should had elaborated more, my apologies Samuel.
DeleteAlso, velocity can be negative while speed will always be positive (since distance is always positive). I liked the examples you used, It helps me understand more!
DeleteDistance is essentially how far you have traveled, so like the total length you walked throughout the school day. Displacement, however, is how far the object is from its original position, so like you start off the day at home, go to school then go back home. Therefore, you have a displacement of zero because you are back where you started.
ReplyDeleteThats a good example of a displacement of zero.
DeleteKind of reminds me of that book, "Around The World In Eighty Days". The protagonist surely gets some distance (around 25,000 miles) but his displacement was zero since he returned back to his home in London.
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ReplyDeleteDistance is the whole distance traveled while displacement is how far it really took from start to finish, a straight line. Also a real world example would be taking a route to your house if you go directly straight to it then it would be close and would be called displacement. However you would have to take other ways because there are obstacles in the way. Therefore it would be distance because you would take a longer route and would be farther.
ReplyDeleteDistance is how far you go, while displacement is how far you go with direction. An example would a race; the distance would be how far the car travels around the course, while the displacement would be 0 since he ended up at the same place.
ReplyDeleteA race track is a great example Joe.
DeleteA race track or a race period is a great example of distance vs. displacement. Good job Joe. :)
DeleteSpeed, being a scalar quantity, does not take into account direction. Velocity, considering that it’s the displacement (not distance) an object travels in respect to time, renders it as a vector quantity since direction is essential. Consider this example. A bee travels 25 m in 5 seconds to the nearest flower. Another bee starting at the same position travels 25 m in 5 seconds but towards the opposite direction. If we were to find the speed of each bee, they would both be 5 m/s. However, if we find the velocity of each bee then one would travel at 5 m/s and the other at -5m/s because we take into account the direction traveled.
ReplyDeleteI really like your explanation. Your example is also very fitting and honestly cleared up some confusion I had between the two. Good job, David!
DeleteDistance is how far you have traveled.Ex.) MacArthur's Cross Country team traveled a distance of 1,195.9 miles to wisconsin for a CC Meet.Displacement, however, is how far the object is from its original position.
ReplyDeleteEx.) The CC Team Will have a displacement of Zero because their final position will be where they started(At MHS).
I liked your example because of how exact it was. Thank you for clearing things up Erik Espinoza.
Deletethis is my favorite example out of the rest ive read.
DeleteYour example is great as well. It was very original.
DeleteDistance is the total amount moved, regardless of the direction changes. Meanwhile, displacement is the word itself. Displacement is the difference between where an object ended up at and the point where it began. ( starting point to end point). An example in the real world would be something like taking your dog for a walk around the neighborhood. Although the distance walked could have been 1 mile, the displacement would be 0m since you returned to the starting point (your home).
ReplyDeleteSpeed is how far an object travels in a given time interval.Whereas, velocity, on the other hand is used to signify both the numerical value of how fast an object is moving and the direction in which it is moving. Speed is always a positive number.
ReplyDeleteEX. A boy longboarding down a hill. The boys speed will increase which would mean that his speed is positive.
The reason why velocity includes direction is because it is displacement divided by time, while speed is distance divided by time.
DeleteDistance is calculated by measuring how much an object traveled with out taking account to direction. Unlike distance, displacement is the measurement of how far an objected moved from its original position taking in account to the direction the object moved. For example if i walk from my room to my kitchen then back to my room my distance traveled would be 40 feet but my displacement would be zero.
ReplyDeleteit also means that you are spending too much time in the kitchen chubby.
DeleteI didn't read your comment and used the exact same example and had to delete it. And well they do say great minds think alike.
DeleteDisplacement is the difference between the final position and the initial position with a final direction, either (-) left or (+) right. On the other hand, distance is the absolute value of the displacement, is always positive and tells how far something is from something else but does not tell whether it is to the right or to the left. For example, displacement can be seen when a swimmer travels from the starting point and back, leaving a displacement value of zero. However, the distance is the total value that the swimmer travels from to the starting point and back.
ReplyDeleteThat is a good example, Gustavo. Makes this a lot clearer.
DeleteI like your example Gus, because it's easy to picture the swimmer swimming laps across the pool and it helps make the distance/displacement a lot clearer to understand.
DeleteHaha! I just realized I used a swimmer too! But I used the concept of speed vs. velocity. Good job Gustavo!
DeleteI had to google the difference but the one thing i got out of distance vs displacement was the initial postion is key. for distance its how much ground an object has covered regardless of final position. am example would be going around the world starting from houston and ending back at houston. the distance would be big but displacement is different. how far out of place an object is displacement which can still apply to going around the world but ending right back where you started you would have 0 meters.
ReplyDeleteWhereas Distance is measured by how far an object has traveled without a direction, Displacement is measured by taking the difference between the final position and initial position while including a direction. For example, a roller coaster begins its course at the starting point. After 1 complete course, The distance would be how far the roller coaster traveled, and the displacement would be 0 since the roller coaster ended up at its starting point.
ReplyDeleteOh yeah! Direction is measured with with displacement. Thanks for the reminder David!
DeleteSpeed and velocity are two terms that are often confused. Speed measures how fast an object is moving. For example, a swimmer is judged on how fast he/she is moving. However, velocity includes direction and it determines the rate at which an object changes position. In a 25 meter pool, the swimmer flip-turns at the end of the pool and essentially changes direction. He or she could be moving faster or slower.
ReplyDeleteAna M.
The one I had most trouble on was displacement vs distance so I chose this opportunity that to really look into it. Displacement is a vector quantity that measures the initial position minus the final position and Distance is a scalar quantity describing the space from one point to another. I looked various examples to see what this really meant. If you start at point A and drive to the mall which is point B the units between the mall and your house is your distance. In the other hand point B minus point a would be your displacement (final-initial).
ReplyDeleteThanks alejandra I was also having trouble with distance and displacement
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ReplyDeleteAll I know about speed and velocity is that one is moving and one is moving at a direction. Speed is determine by a scalar level or how fast an object is moving while, velocity is a vector in which the rate an object moves to change a direction. They are similar as they deal in both speed but one is different from the other. That different is one is a vector and one is a scalar. A real world example would be Martha is driving on a dirt road. She is driving at a speed of 60mph. Although, at the rate she is driving, she decides to drive eastward. Making the vector change from north to east. So she is now driving 60mph east.
ReplyDeleteDon`t forget Cody that speed is always positive. And its great that you mentioned velocity being a vector i had completely forgotten!
DeleteThe distance is the length between two points and the path connecting them.While displacement is the length of an imaginary straight path, typically distinct from the path actually traveled.Ex:The distance from the locker room to my last class of the day and back to the locker room to get my stuff feels like 5 miles. Surprisingly the displacement is zero, because I end up right where I started.
ReplyDeleteDisplacement is different from distance because displacement measures the distance traveled from your final position in respect to your initial position. Distance measures your total amount traveled. For example, walking from the park entrance all around the park and coming back to the park entrance would have 0 displacement because I ended where I started.
ReplyDeleteThe difference between speed and velocity is the one uses a scalar quantity and the other one used a vector quantity. Speed is the average rate of change of an object's position and velocity is the measurement of the rate and the direction its been traveled. For example a cross country runner running a certain amount of miles in a certain amount of time can give you the speed. However if one simple does not know the direction the runner is running then velocity cannot be calculated.
ReplyDeleteyou made things a lot clearer for me! Though I am not a cross country runner, this scenario was really helpful!
DeleteThis was a really well put example and helped me understand how speed and velocity works bit better.
DeleteI think that you should have put actual numbers in the example of the cross country runner so i could actually work out the problem and check my answer with yours.
DeleteSpeed is a scalar quantity that determines how fast an object is moving in a given time, since speed a scalar quantity it does not necessarily correlate with distance. An example would be a little boy jogging through his neighborhood, he traveled 100 meters in 10 minutes. His speed would be 10 meters per minute. Now, velocity is a vector quantity which means the rate of change in an objects position. Velocity is correlated with direction. An example would be a race car driver going 125 miles per hour in the north direction which would be his constant velocity.
ReplyDeleteAh! i wanted to say direction on line two!
Deletethe difference between displacement and distance is displacement is how far an object has gone from it's initial start while distance is how far an object has gone. The difference between speed and velocity is that velocity had direction while speed does not. A race track would be a great example because the vehicles are moving at different speeds in the same circular track.
ReplyDeleteSpeed also constantly stays positive.
DeleteThe difference between speed and velocity is speed is just a speed going and a velocity is like speed but has a sense of direction a long with it. Displacement is the difference from how far the object went from its initial starting position and distance is just how far it went all together.
ReplyDeleteI like how your definitions are very straight forward and they actually make sense.
DeleteSpeed is the rate at which something is able to move while velocity is the speed of something in a given direction. Speed is a scalar quantity and velocity is a vector quantity. Example of speed: a train goes 30m/s. Example of velocity: a train going 30 m/s South.
ReplyDeleteSpeed is how fast something goes with no given direction and its a scaler quantity a good example would be of speed would be the boy ran a mile in 5 minutes. Velocity on the other hand has a given direction and is vector quantity. A good example would be the plan traveled 50m/s south towards wisconsin.
ReplyDeletegood example kim ! good way of using your cross country encounters into explaing physics
DeleteSpeed is always seen as a positive motion along with also not having a defined direction. Velocity is basically the vice versa of speed because it can be positive or negative and also had a definite direction unlike speed. One example could actually be a marching band because speed would remain constant until the tempo was changed then it would go to velocity.
ReplyDeleteIt's not neccessarily the exact opposite but it is at the total distance traveled instead of how further it got from the beginning.
DeleteSpeed is always positive no matter what direction is going. Also speed is measuring the total distance traveled divided by the time. Velocity is the change in distance divided by the time and this can be negative because they objects can travel back. One example, lets say I used my bike for 200 meters in 60 seconds, my speed would be 3.33 k/sec.
ReplyDeleteI agree with what you say.
Deletespeed is used to measure how fast an object is moving without direction. velocity is used to measure how fast an object is moving in a certain direction. you could measure a soccer player's speed instead of his velocity because a soccer player runs all over the field and not in just one certain direction. you could measure a sprinter's velocity because they run in a direct straight lane in a certain direction plus they would have displacement because velocity is displacement/time while speed is just distance/time.
ReplyDeleteDistance is the total distance you have traveled, while displacement is the distance from the original starting point to the last. An example for distance is the miles it took from home to school. An example for displacement is a race car racing in a loop, its beginning and its end are the same so its displacement is 0.
ReplyDeleteThe difference between speed and velocity is that while speed does not have direction, velocity does. Also, speed is always positive, but velocity can be negative, due to the fact that distance is always positive but displacement can also be negative. An example of speed would be a cheetah running across a plain. An example of velocity would be a tornado traveling across land. The weatherman would be expressing its velocity as "60 mph N".
ReplyDeleteThe difference is velocity is speed with a direction but speed has no direction. Speed can't be negative its always positive. Velocity can be both negative and positive. An example of speed is when a antelope run away from a lion. An example of velocity is when a tsunami hits land.
ReplyDeleteWell speed is the absolute value of velocity. Meaning direction does not influence it's magnitude. Thus this is why cars use speedometers which measure speed. Not velocity.
ReplyDeleteSpeed is fast one is going at an absolute value while the velocity is the speed in a certain direction in a given moment.
ReplyDeletedistance vs displacement and speed vs velocity. Distance and displacement correspond with each other, distance doesn't have a positive or or negative value but displacement does. Acceleration and velocity, I feel like acceleration is harder to understand than velocity because velocity curves with time and displacement and velocity is a constant straight line that changes with specific slopes.
ReplyDelete