question form

#$&*

Phy 121

Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** Question Form_labelMessages **

Question on vectors

** **

** **

Some of the problems with vectors that I have run across I am not really understanding how to do them....for example, one asks What vector of magnitude 6.6 must be addedto A= <-.55, 6.4> in order to obtain a vertical vector? How would I find the magnitude and angle of the vector that is suppossed to be added?

and another one talks about the velocity of a vector bas x and y components -3 meters/sec and 10 meters/sec....how would you find the magnitude and angle displacement in this case...?? Thank you!!

** **

@&

See also the Introductory Problem Sets, where more extensive explanations are provided. All problems on your test are generated by the same program that generates those sets.

A vertical vector has x component 0. So to get a vertical vector you would have to add a vector whose horizontal component is +.55.

The vector would therefore have magnitude 6.6, with horizontal component .55.

Thus

sqrt( (.55)^2 + (vert comp)^2) = 6.6 so

.55^2 + (vert comp)^2 = 6.6^2

and

(vert comp)^2 - 6.6^2 - .55^2

so

vert comp = +- sqrt( 6.6^2 - .55^2).

The magnitude and angle of a vector whose components are R_x and R_y are

magnitude = sqrt( R_x^2 + R_y^2)

angle = arcTan(R_y / R_x_), plus 180 deg if R_x = 0.

*@