InterviewSolution
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InterviewSolution
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The position vector of a aprticle is given as `vecr=(t^2-4t+6)hati+(t^2)hatj`. The time after which the velocity vector and acceleration vector becomes perpendicular to each other is equal toA. 2 secB. 1 secC. 1.5 secD. 5 sec |
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Answer» Correct Answer - B `vec r =(t^2 - 4t + 6) hat i + t^2 hatj , vec v = (d vec r)/(dt)` =`(2t - 4)hat i + 2t hat j, vec a = (d vec v)/(dt) = 2 hat i + 2 hat j` If `vec a` and `vec v` are perpendicular, `vec a. vec v = 0` `(2 hat i + 2 hat j).((2 t - 4) hat i + 2t hat j) = 0` `8t - 8 = 0, t = 1 sec`. |
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