Acceleration problem. me vs book

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SUMMARY

The discussion centers on a physics problem involving a bus accelerating from an initial speed of 30.0 km/h at a constant rate of 3.5 m/s² over a duration of 6.8 seconds. The book states the final velocity as 120 km/h, while the user calculates it to be approximately 115.67 km/h. The discrepancy arises from the consideration of significant figures, where the book rounds the answer to two significant figures. The user confirms their calculations are correct, acknowledging the importance of significant figures in reporting results.

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Homework Statement


A bus is traveling at 30.0 km/h speeds up at a constant rate of 3.5 ms/^2. What velocity does it reach at 6.8 seconds later?

book says 120.km/hour
I get 115 km/hour

Homework Equations


Vf=Vi+a x delta t


The Attempt at a Solution


First I changed 30.0 km/hour to 30000 m/3600s then reduced to 8.3 m/s. Used formula to get Vf=32.13m/s

I divide 32.13 by 1000 to get .03213 km/s then 1.9278 km/m then 115.668 km/h.

I've worked this problem a hundred different ways and get the same answer. AM i right or the book?
 
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Looks like you and the book are correct. I would assume that the book is answering the question to 2 significant figures, thus 115.668km/h is 120km/h assuming your math is correct.
 
oh my goodness i forgot all about sig figs. Thank you very much
 

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