# Homework Help: Just some language

1. Sep 29, 2004

### Alkatran

Which statements are true?

A) A vector can have zero magnitude if one of its components is not zero.
B) If a + b = c and a2 + b2 = c2, then the angle between a and b is 90°.
C) Two vectors having different magnitudes can be combined to give a vector sum of zero.
D) The magnitude of the difference between two vectors can be greater than the magnitude of at least one of the vectors.
E) If a + b = c and a2 + b2 < c2, then the angle between a and b is between 0° and 90°.
F) Three vectors which do not lie in the same plane can never give a vector sum of zero.
G) If a + b = c and a + b = c, then the angle between a and b is 180°.

I've got: FTFTTTF

I just need some help translating what these questions mean
A: Components are the x,y,z components. Magnitude has to be > 0
B: Is it a length or a vector? I know that since they're perpendicular two vectors squared WILL equal...
C: Obviously if one is shorter than the other it can't undo the other completely
D: Opposite directions. True
E: I'm not sure. But I think this is true... unless than angle can be greater than 90?
F: True
G: In the question the first a + b = c is bold and the second is italics, that's the only difference between them. I highly doubt it change their meaning, other than that I think G is false.

2. Sep 29, 2004

### Alkatran

Got it.

Why can't I delete the post?