A rubber ball dropped on a hard surface takes a sequence of bounces, each one 1/6 as high as the preceding one. If this ball is dropped from a height of 12 feet, how far will it have traveled when it hits the surface the fifth time?

Respuesta :

Answer:

[tex]\frac{259}{54}\text{ or }4.8\text{feet}[/tex]

Step-by-step explanation:

GIVEN: A rubber ball dropped on a hard surface takes a sequence of bounces, each one [tex]\frac{1}{6}[/tex] as high as the preceding one.

TO FIND: If this ball is dropped from a height of [tex]12[/tex] feet, how far will it have traveled when it hits the surface the fifth time.

SOLUTION:

once the ball is dropped on hard surface it bounces [tex]\frac{1}{6}[/tex] of preceding one and comes down the same distance.

When the ball is dropped from [tex]12[/tex] feet height

after first hit [tex]=12\times\frac{1}{6}\text{ up}+12\times\frac{1}{6}\text{ down}=4[/tex]

new height [tex]=12\times\frac{1}{6}=2\text{feet}[/tex]

after second hit [tex]=2\times\frac{1}{6}\text{ up}+2\times\frac{1}{6}\text{ down}=\frac{2}{3}[/tex]

new height [tex]=2\times\frac{1}{6}=\frac{1}{3}\text{ feet}[/tex]

after third hit  [tex]=\frac{1}{3}\times\frac{1}{6}\text{ up}+\frac{1}{3}\times\frac{1}{6}\text{ down}=\frac{1}{9}[/tex]

new height [tex]=\frac{1}{3}\times\frac{1}{6}=\frac{1}{18}\text{ feet}[/tex]

after fourth hit [tex]=\frac{1}{18}\times\frac{1}{6}\text{ up}+\frac{1}{18}\times\frac{1}{6}\text{ down}=\frac{1}{54}[/tex]

adding all distance [tex]=4+\frac{2}{3}+\frac{1}{9}+\frac{1}{54}[/tex]

                                 [tex]=\frac{259}{54}[/tex] feet

Hence the ball will travel   [tex]\frac{259}{54}[/tex] feet before it hits the surface fifth time.