Question

If the energy of ball falling from a height of 10m is reduced by 40% how high will it rebound??

Answer 1

$Data : h1 = 10m$

$E2 = E1 - E2 = E1 - E1 × ⁴⁰/100$

$》E1 ( 1 - 0.4 ) = 0.6 E1 , H2 = ?$

$》E1 = mgh1 , E2 = mgh2$

$》E2 = 0.6 E1$

$Therefore H2 = 0.6 H1 = 0.6 × 10m = 6m$

Answer 2

$\bf\huge\underline{ANSWER}$

》As the GPE of a falling body is given by GPE = mgh, then if 40% of the total energy is turned into other forms, only 60% will remain as GPE when it bounces to its maximum height, and its rebound height will be 60% of its original height.

》If it was droppped from an original height of 10m, it will rebound to 6m.