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DOJO
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#1
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Can someone please explain the concept behind displacement to me, as I know what Speed, acceleration and velocity is...

Thanks.
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Syncman
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from my understanding displacement is just a linear distance from the starting point in most cases.
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danmint
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total distance moved measured from start to finish.
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DOJO
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(Original post by danmint)
total distance moved measured from start to finish.
I thought the velocity was the magnitude from start to finish
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DOJO
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(Original post by DOJO)
I thought the velocity was the magnitude from start to finish
and the speed is the constant speed that the magnitude travels from start to finish ,whereas the acceleration is the change of speed within the magnitude.
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shift3
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displacement is the distance from the starting point.
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Gauss
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(Original post by DOJO)
I thought the velocity was the magnitude from start to finish
Velocity is not the magnitute, it is a vector which has a magnitude and direction.

Displacement is the distance one travels from a point. Say you walk forwards 10m, then your displacement is 10. Whereas if you walk 10m forwards and decide to walk 12m backwards then your displacement is -2.

Galois.
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DOJO
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(Original post by Galois)
Velocity is not the magnitute, it is a vector which has a magnitude and direction.

Displacement is the distance one travels from a point. Say you walk forwards 10m, then your displacement is 10. Whereas if you walk 10m forwards and decide to walk 12m backwards then your displacement is -2.

Galois.
So velocity is the direction of vector and the displacement is the total distance of that vector?
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Syncman
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Easy way is.

Velocity = Speed + direction

Displacement = Distance from start

E.g.

A ball is dropped 1m hits the floor and bounces back 1m in the air.
the total displacement is 0. because the ball is back where it started.
Also the balls starting velocity is 0 and finishing velocity is 0. and acceleration is gravity (-9.8) NOTE. acceleration has a direction.

OR

A car passes point A at 20ms^(-1) accelerates at 5ms^(-2) for 100m until it passes B.
In this case displacement is 100m.

Remember always draw a diagram and CLEARLY label the direction of positive.
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Gauss
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(Original post by DOJO)
So velocity is the direction of vector and the displacement is the total distance of that vector?
You cannot say "distance of that vector". A vector represents two things: magnitude and direction. In this case velocity is a vector; it's direction is the direction of motion, and it's magnitude is given by speed.

Similarly for displacement, it gives you two pieces of information:
1) How far away you are from a point you started moving from
2) In which direction you are (linearly)

Obviously if the displacement is negative then it indicates you have moved "backwards" from a point. Also if the displacement is 0 it only says that you are at the same point. If one particle moves forwards 10m and back 10m, and another particle moves forwards 12m and back 12m then both they're displacement is 0, although the former moved 20m yet the latter 24m.

Displacement does not necessarily tell you how much you have moved, only where you are from a specific point.

Hope that clears it up.

Galois.
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