Select the most appropriate answer for the following questions.

A force of magnitude 60 kN makes an angle of 30° with positive x-axis. Its component about y-axis will be

  (i) 34.64 kN                   

  (ii) 30 kN                            

  (iii) 40 kN

2

A point P is subjected to two collinear forces F1 and F2 in such a way that it is in equilibrium. If F1 = 6i –  2j + 3k then F2 will be

  (i) F2 = – 6 i + 2j – 3k       

  (ii)  F2 = 2i + 6j + 4k                 

  (iii) None

The position vector for a point P (2,3,4)  is directed from the origin O (0,0,0) of the coordinate axes  towards the point. It can be written as

 (i) OP = 2i + 3j + 4k     

 (ii) OP = 4i + 3j + 2k           

 (iii) None of these

A force of 10 kN is acting as shown in the following figure. Find the moment of the force about point P.

 (i)   20 kNm                

 (ii)  10 kNm             

 (iii)   None of these

A force vector  F of  5 units acting at a point is directed along positive x-axis. It can be represented as

(i) F = 5 k                   

(ii) F = 5 i                 

(iii) F = 5 j