- #1
nodtomc
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The tangential velocity of a body rotating about the centre point "O" is given by v=w.r, where w is angular velocity and r = radius. give that the vectors
w = 3i - 2j + 7k
r = 2i + 5j - 3k
a) Calculate the magnitude of velocity
b) the vector product in the form i+j+k
So far I have the vector product as -29i +23k + 19k. I am a little confused when it comes to caclulating the magnitude of velocity. Do I do the magnitude of the vector product using Pythagoras? Or do I do the dot product of the w and r vectors?
I have the answers, 41.61m/s, or 25m/s from using either method.
I think I'm being a little thrown off by a few things;
the word magnitude in the question, although I'm under the assumption that magnitude of velocity is speed?)
The fact that velocity is a vector quantity.
I also have a question on work done, which again, as it's scalar quantity, I'm being a little thrown off by the fact it's a scalar quantity, so do i use dot/scalar product, or magnitude of the vector product?
EDIT: worth mentioning it's coursework so ideally if you can just hint at the right direction to follow, that would be appreciated
Thanks
w = 3i - 2j + 7k
r = 2i + 5j - 3k
a) Calculate the magnitude of velocity
b) the vector product in the form i+j+k
So far I have the vector product as -29i +23k + 19k. I am a little confused when it comes to caclulating the magnitude of velocity. Do I do the magnitude of the vector product using Pythagoras? Or do I do the dot product of the w and r vectors?
I have the answers, 41.61m/s, or 25m/s from using either method.
I think I'm being a little thrown off by a few things;
the word magnitude in the question, although I'm under the assumption that magnitude of velocity is speed?)
The fact that velocity is a vector quantity.
I also have a question on work done, which again, as it's scalar quantity, I'm being a little thrown off by the fact it's a scalar quantity, so do i use dot/scalar product, or magnitude of the vector product?
EDIT: worth mentioning it's coursework so ideally if you can just hint at the right direction to follow, that would be appreciated
Thanks