Question

V
. A vector of length 'm' is turned through an
angle B about its tail. The change in the
position vector of its head is
​

Answer 1

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step by step :

Using parallelogram law:

∣  

R

∣=  

(l  

2

+l  

2

−2l  

2

cosθ)

​

 

∣  

R

∣=l  

2(1−cosθ)

​

 

∣  

R

∣=l  

2(2sin  

2

(  

2

θ

​

))

​

 

∴∣  

R

∣=2lsin(  

2

θ

​

)