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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: wildareal on March 25, 2010, 09:17:52 pm

Title: Sequences and Series Question
Post by: wildareal on March 25, 2010, 09:17:52 pm: A ball dropped from a height of 15m rebounds from the ground to a height of 10m. With each successive rebound, it rises two-thirds of the height of the previous rebound. What total distance will it have traveled when it strikes the ground for the 10th time.
Title: Re: Sequences and Series Question
Post by: qshyrn on March 25, 2010, 09:34:05 pm: using the formula for geometric seriess ~~s=15((2/3)^10-1)/((2/3)-1) =44.22cm~~
edit: this is wrong cuz as mao pointed out, i ddidnt consider the ball goin down :uglystupid2:
Title: Re: Sequences and Series Question
Post by: Mao on March 25, 2010, 11:39:52 pm: Quote from: qshyrn on March 25, 2010, 09:34:05 pm
using the formula for geometric seriess s=15((2/3)^10-1)/((2/3)-1) =44.22cm

No. You need to account for the up AND down motion of the ball.

The actual answer is $2s - 15 \approx 73$ .
Title: Re: Sequences and Series Question
Post by: qshyrn on March 25, 2010, 11:47:52 pm: Quote from: Mao on March 25, 2010, 11:39:52 pm
Quote from: qshyrn on March 25, 2010, 09:34:05 pm
using the formula for geometric seriess s=15((2/3)^10-1)/((2/3)-1) =44.22cm

No. You need to account for the up AND down motion of the ball.

The actual answer is $2s - 15 \approx 73$ .
oops silly me.i remember doing this problem in gma