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Grade 7Vectors

The square of the resultant of two forces 4 Newtons and 3 Newton exceeds the square of the resultant of the two forces when at right angles by 12 the angle between the forces is

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Profile image of Pandu Sushanth
8 Years agoGrade 7
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1 Answer

Profile image of Arun
8 Years ago
Let angle between 3 and 4 is @
 
then
 
R^2 =  9 + 16 + 24 cos @
 
and also according the question,
 
R^2 = (sqrt(3^2 + 4^2))^2 + 12
 
R^2 = 25 + 12
 
25 + 24 cos @ = 37
 
cos @ = 12 / 24 = ½
 
@ = 60 degree
 
hence option 2 is correct