Math Is Fun Forum

atran

Member

Registered: 2013-07-12

Posts: 91

Quantity, Magnitude, Unit

Hi,

There are at least two types of quantity: scalar quantity and vector quantity. Both have magnitude, but only the vector quantity has direction. A unit is a magnitude. Thus, if F is a vector quantity, then |F| is the magnitude of the quantity.

Am I thinking right?
Thanks for help...

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Quantity, Magnitude, Unit

|F| is the norm or Euclidean distance from the origin of the vector F,

Sometimes it is written like this.

There are other types of norms.

What is A unit?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

atran

Member

Registered: 2013-07-12

Posts: 91

Re: Quantity, Magnitude, Unit

Say x=10 metres: is the magnitude of x 10 or 10 metres? I believe the latter is true.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Quantity, Magnitude, Unit

The magnitude is 10 meters.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

atran

Member

Registered: 2013-07-12

Posts: 91

Re: Quantity, Magnitude, Unit

Hi;

The magnitude of a number is its absolute value.
The magnitude of a vector is its length.
The magnitude of a scalar (e.g -10°) is the quantity itself.

Am I thinking right?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Quantity, Magnitude, Unit

Magnitude is always a positive. A scalar is any number. It can be positive or negative.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.