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JEE Main20199 Apr 2019Evening ShiftPhysicsMotion in One DimensionActual

The position vector of a particle changes with time according to the relation r → t = 15 t 2 i ^ + 4 - 20 t 2 j ^ . What is the magnitude of the acceleration at t = 1 ?

Options

  1. A40
  2. B25
  3. C100
  4. D50

Correct answer

D. 50

Step-by-step solution

r → = 15 t 2 i ^ + 4 - 20 t 2 j ^ v → = 30   t i ^ - 40 t   j ^ a → = 30   i ^ - 40 j ^ At t = 1 , a → = 30   i ^ - 40 j ^ a → = 50

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