Vector Change (1 Viewer)

[kurt.physics]

Could some one explain this to me, im currently working out of Excel Preliminary Physics and i cant quite seam to get my head around it. Its page 97.

 

[kurt.physics]

Also, i just have this thing with displacement, could you explain your way?

Here is what i think, displacement is of course a vector, as it is the vector equivelent of the distance scalar, it is the distance and direction of the shortest route from point A to point B.

Is that write, could you pehaps add to it?

 

[S1M0]

What exactly are you having trouble with in grasping vectors?

 

[S1M0]

Displacement is a vector quantity. That is, it is the measure of distance with respect to the direction of that distance.

Think of it this way.

Imagine a straight number line with a particle (or a dot) above it. We assume a positive direction and a negative direction. Logically, positive direction is to be the opposite of the negative direction and vice versa.

For the sake of argument, we assume that right is the postivie direction.

If the particle moves to the right by say 4 units, its displacement is 4 units positive.

If the particle, at rest, moves 3 units to the left, than its displacement is -3 units.


So to sum it up:

Distance in respect to direction = Displacement.

 

[vds700]

ill try to explain the example in excel...

basically they have added the 2 vectors together to find the resultant vector, which is the change n velocity. To add vector lines together, you draw a line from the tail of the first vector to the head of the second vector. So in the case of the billiard ball, u draw a vector line from the tail of the first vector to the head of the 2nd vector, ie a horizontal straight line. Use pythagoras to find the magnitude of the vector. sqrt(4^2 + 4^2) = 5.7. And obviously it is 90 degrees away from the normal to the table edge.

You're that year 9 kid doing accelerated maths right ??? Physics too? Can i ask why youre going so far ahead??

 

[kurt.physics]

ill try to explain the example in excel...

basically they have added the 2 vectors together to find the resultant vector, which is the change n velocity. To add vector lines together, you draw a line from the tail of the first vector to the head of the second vector. So in the case of the billiard ball, u draw a vector line from the tail of the first vector to the head of the 2nd vector, ie a horizontal straight line. Use pythagoras to find the magnitude of the vector. sqrt(4^2 + 4^2) = 5.7. And obviously it is 90 degrees away from the normal to the table edge.

You're that year 9 kid doing accelerated maths right ??? Physics too? Can i ask why youre going so far ahead??

Thanks, I accelerate because i enjoy the topics, i have had a deep interest in physics for a while and that made me want to learn calculus to understand more physics, so last year i learnt calculus and got hooked on mathematics and so now im hooked on both physics and maths so yeh.

Um, so yeh, i still dont understand, it asks what the change in velocity is, the magnitude doesnt change, only the direction, so why is its magnitude changed to 5.7 and not 4 as it just bounced at a 90 degree angle?

 

[kurt.physics]

Also, what does that line mean?

 

[vds700]

Thanks, I accelerate because i enjoy the topics, i have had a deep interest in physics for a while and that made me want to learn calculus to understand more physics, so last year i learnt calculus and got hooked on mathematics and so now im hooked on both physics and maths so yeh.

Um, so yeh, i still dont understand, it asks what the change in velocity is, the magnitude doesnt change, only the direction, so why is its magnitude changed to 5.7 and not 4 as it just bounced at a 90 degree angle?

well, change in velocity is change in displacement over time right? So the resultant vector shows the change in displacement of the ball from its original position.

Listen, if you're gonna teach yourself physics (im assuming youre not in a class), excel is shit for that. It doesn't even cover the whole course, ie there are some things missing. My advice would be to get jacaranda physics, it has good info on the concepts plus good worked examples.

 

[kurt.physics]

Listen, if you're gonna teach yourself physics (im assuming youre not in a class), excel is shit for that. It doesn't even cover the whole course, ie there are some things missing. My advice would be to get jacaranda physics, it has good info on the concepts plus good worked examples.

Thanks, yeh i used jacaranda and it is amazing, i love it! Its just that the only copy is at the school library and because its the holidays, i cant get to it

I will just wait untill the start of school, but yeh, ive had dificulties with excel, dont quite fancy it myself.

Thanks