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An object is dropped from a height h from the ground.  Every time it hits the ground it looses 50% of its kinetic energy.  The total distance covered ast\rightarrow \infty is :

  • Option 1)

    3h

  • Option 2)

    \infty

  • Option 3)

    \frac{5}{3}h

  • Option 4)

    \frac{8}{3}h

 

Answers (3)

best_answer

As we have learned

3rd equation or Velocity –displacement equation -

V^{2}-u^{2}=2as

V\rightarrow Final Velocity

s\rightarrow Displacement

u\rightarrowInitial velocity

a\rightarrowacceleration

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Initial height covered h_0 = h

At the point of impact , velocity 

                                       v_0 = \sqrt{2gh}

After losing its kinetic energy 

by 50 % velocity v_1 = 1/2 v_0 = \sqrt {gh }

\Rightarrow h_1 = \frac{v_{1}^{2}}{2g } = h /2 \Rightarrow   Tota l distance after 1st collision = 2 h_1 = h

Similarly  h_2 = h /4 , h_3 = h/8

Total distance covered 

= h + 2h_1 + 2 h_2 + .... \infty \\ = h + h + h/2 ...\infty \\ = 2h + h/2 (1+ 1/2 ...\infty )

= 2 h + h/2 (1-1/2 ) = 3 h

 

 

 

 

 

 

 


Option 1)

3h

Option 2)

\infty

Option 3)

\frac{5}{3}h

Option 4)

\frac{8}{3}h

Posted by

SudhirSol

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2

Posted by

vishal dange

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First is right answer, because every time it hit ground it cannot  much distance

Posted by

Omkar Kadam

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