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A certain ball, when dropped to the ground, rebounds to 4/5th of the height from which it falls. If it is dropped from a height of 300 m, what is the total distance it travels before coming to rest?

a. 300 m
b. 450 m
c. 600 m
d. 750 m

User Akbapu
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1 Answer

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Final answer:

The ball travels a total distance of 1200 meters before coming to rest, calculated using the sum of an infinite geometric series with the first term being 300 meters and the common ratio being 4/5.

Step-by-step explanation:

To determine the total distance the ball travels before coming to rest, we need to consider both the descent and ascent distances for each bounce. Since the ball rebounds to 4/5ths of the previous height, we have a geometric series where the first term is 300 m (the initial drop) and the common ratio is 4/5. The total distance traveled by the ball is the sum of the infinite geometric series:

  • First drop = 300 m
  • First rebound = 300 m * (4/5) = 240 m
  • Second drop = 240 m
  • Second rebound = 240 m * (4/5) = 192 m
  • and so on...

We calculate the sum of the infinite series using the formula:

S = a / (1 - r)

where S is the sum of the series, a is the first term, and r is the common ratio.

In this case, a = 300 m and r = 4/5. Plugging these values into the formula:

S = 300 / (1 - 4/5) = 300 / (1/5) = 300 * 5 = 1500 m

However, this includes both the ascent and descent of each bounce. Since the initial drop doesn't have a preceding ascent, we must subtract one initial height of 300 m to obtain the total distance traveled:

Total distance = 1500 m - 300 m = 1200 m

Therefore, the ball travels a total distance of 1200 meters.

User Dronacharya
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