saikrishnadee said:
What do you mean by displacement has direction . When we generally mention in a problem then we just tell 20m , not 20m N ! So what actually do you mean by direction
And there's sumthing like this right
scalar x scalar = vector
How many equation like that are there ?
Usually when we talk about a vector quantity, we make it negative or positive depending on its direction. And "20m" on its own is not a vector quantity, unless you have already stated that a positive distance means north (and a negative one means south).
You are right: "20m" is a distance (scalar), "20m N" is a displacement. Just sometimes the "N" is not actually written, it is just known in your head, or drawn on a diagram.
This only covers one dimensional vectors, where only two directions are taken into account.
If you have a two dimensional plane, and you have a force, F, acting in a peculiar direction. Then you could either say:
1. The force F = (3
i + 4
j)N *
2. F = 5N at an angle of about 53 degrees.
* N is not North, N is Newtons in this context. And the
i and
j are "perpendicular unit vectors". What this basically means is that the force F is equivalent to two separate forces: one of them is 3 Newton
left, and the other is 4 Newtons
Up.
Both 1 and 2 are valid ways of writing the same vector force.
As for scalar*scalar = vector
Im not sure, I know you get scalar*vector=vector
e.g. F=ma, The direction of F is exactly the same as the direction of a.
and vector*vector=vector
v=at (velocity = acceleration*time, if the initial velocity is zero)