length of the vector is proportional to the magnitude of the vector
so length of vector will be in the proportional to the magnitude of the vector here
initial length of the vector is 3 cm which represent the velocity vector as 100 m/s
now it means 3 cm length is proportional to speed which is 100 m/s
now if we draw another vector of length 6 cm then here we can see that if length of vector is doubled then initial length
so here the magnitude of velocity will also be doubled
so here final speed must be double of initial speed
[tex]v_f = 2* v_i[/tex]
[tex]v_f = 2*100 = 200 m/s[/tex]
