Question

4 A rubber ball is dropped from a certain height. It is
found to rebounce only 90% of its previous height-
If it is dropped from the top of a 25m. tall building to
what height would it raise after bouncing on the
ground 2 times.​

Answer 1

Nice question!

$\mathcal{\green{\underline{\blue{GIVEN:}}}}$

• The rubber ball is dropped from a building 25 m tall. (h=25 m)
• It is found that it bounces 90% of its height in its first bounce.

$\mathcal{\green{\underline{\blue{TO \:\: FIND:}}}}$

• To find the height after it bounces 2 times.

$\mathcal{\green{\underline{\blue{SOLUTION:}}}}$

First, find the height in the first bounce.

It decreased by 90%

We need to find 90% of max-height:

$\implies \sf 90\% \:\: of \:\: 25:$

$\implies \frac{90}{100} \times 25$

$\implies\boxed{\sf{\blue{22.5 m}}}\end{gathered}$

∴It travelled 22.5 m in the first bounce.

Now, again apply the same principle... :)

It decreased by 90%

We need to find 90% of the bounced height:

$\implies \sf 90 \% \:\: of \:\: 22.5:$

$\implies \frac{90}{100} \times 22.5$

$\implies\boxed{\sf{\blue{20.25 m}}}\end{gathered}$

$\boxed{\bold{\large{20.25m \:\: is \:\: the \:\: required \:\: answer. }}}$

$\huge\star\:\:{\orange{\underline{\pink{\mathbf{HOPE \:\: THIS \:\: HELPS \:\: :D}}}}}$