hi goiitians plz help me with these ques.

ques 1 a dimensionless quantity

 never has a unit

 always has a unit

  may hav a unit

  doesn't exist

 expected ans a

reason a unitless quantity never has a nonzero dimension so by converse

 hcv ans c

ques 2 a vector A points vertically upward and B points towards north .



       then    is

  along west



 



  along east



 



  zero



  



  vertically downward

expected ans c

reason my view is north n vertically upward diections r same

h.c.v ans a

ques 3 the x component of resultant of several vectors

  is equal to sum of x component of the vector

  may be smaller than than the sum of magnitude of vectors

  may be greater than the sum of magnitude of vectors

  may be equal to sum of the magnitude of vectors 



  

expected ans nil

reason i didn't get this

h.c.v ans a b d

Question 1

Dimensionless quantities may have units. For example : Angle is a dimensionless quantity, but one of its unit is "radian".

Question 2

If we consider the +ive x - axis, +ive y - axis and +ive z - axis, then  X  X  Y =  Z ie, X  X  Y is along +ive z - axis

Now consider the vector A pointing vertically upwards( along +ive x - axis ) and B pointing north ( along +ive y - axis ), then A X B is along the +ive z - axis, that is, along the west.