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1]If A = B+C and the magnitude of A, B and C are 5,4,3 unit, the angle between A and B is : (a)cos -1 3/5 (b) cos -1 4/5 (c)π/2 (d) sin -1 3/5 2] Unit vector parallel to the resultant of vectors 4i – 3j and 8i + 8j and 8i + 8j will be: (a) (24i+5j)/13 (b) (12i+5j)/13 (c) (6i+5j)/13 (d) none of these 3] A force of 6 N and another of 8 N can be applied together to produce the effect of a single force of: (a) 1 N (b) 11 N (c) 15 N (d) 20 N 4] Two vectors having equal magnitudes A make an angle ? with each other. The magnitude and direction of the resultant are respectively: (a) 2Acos ? /2, along bisector (b) A cos ?/2, at 45 from one vector (c) A cos ?/2, along bisector (d) A sin ?/2, along bisector


1]If A = B+C and the magnitude of A, B and C are 5,4,3 unit, the angle between A and B is :


(a)cos-13/5                          (b) cos-14/5


(c)π/2                                    (d) sin-1 3/5



2] Unit vector parallel to the resultant of vectors 4i – 3j and 8i + 8j and 8i + 8j will be:


(a) (24i+5j)/13                   (b) (12i+5j)/13


(c) (6i+5j)/13                      (d) none of these


3] A force of 6 N and another of 8 N can be applied together to produce the effect of a single force of:


(a) 1 N                   (b) 11 N


(c) 15 N                 (d) 20 N


4] Two vectors having equal magnitudes A make an angle ? with each other. The magnitude and direction of the resultant are respectively:


(a) 2Acos ? /2, along bisector


(b) A cos ?/2, at 45 from one vector


(c) A cos ?/2, along bisector


(d) A sin ?/2, along bisector

Grade:11

1 Answers

AKASH GOYAL AskiitiansExpert-IITD
420 Points
13 years ago

Dear Anand

1. A-B=C square both sides

25+ 16-40 cos@=9  , cos@=32/40 = 4/5 ans b

2. resultant vector sum of all three = 20i + 13j  hence d

3. resultant square= 36 + 64 + 96 cos@= 100 + 96 cos@ range 4 to 196 

 resultant 2 to 16 answer b

4. R2= 2A2 + 2A2 COS@= 2A2 (1+COS@)=2A2 2COS2@/2

     R= 2ACOS@/2 option a

 

All the best.                                                           

AKASH GOYAL

AskiitiansExpert-IIT Delhi

 

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