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KCET2008MathematicsParabola

A stone is thrown vertically upwards and the height x ft reached by the stone in t seconds is given by x=80 t-16 t² . The stone reaches the maximum height in

Options

  1. A2 ~s
  2. B2.5 ~s
  3. C3 ~s
  4. D1.5 ~s

Correct answer

B. 2.5 ~s

Step-by-step solution

Given, x=80 t-16 t² On differentiating w.r.t. , we get dx dt =80-32 t Since, the stone reaches the maximum height, then velocity will be zero ( . ie, . dx dt =0 ) Let y= x x 80-32 t=0t=2.5 ~s

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