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JEE Main202125 Feb 2021Evening ShiftPhysicsMotion in One DimensionActual

A stone is dropped from the top of a building. When it crosses a point 5 m below the top, another stone starts to fall from a point 25 m below the top. Both stones reach the bottom of building simultaneously. The height of the building is :

Options

  1. A25   m
  2. B45   m
  3. C35   m
  4. D50   m

Correct answer

B. 45   m

Step-by-step solution

Time for particle to meet = t ' = S r e l S r e l = 20 10 = 2   sec Time taken by I s t particle to reach ground = 3   sec H = 1 2   g 3 2 = 45   m

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