SOLUTION: If you are excelerating from 40 mph to 70 mph down a road and it takes you 9.8 seconds. How many feet will you have traveled?

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Question 390828: If you are excelerating from 40 mph to 70 mph down a road and it takes you 9.8 seconds. How many feet will you have traveled?
Found 2 solutions by richard1234, Alan3354:
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Not enough information, since we don't know the rate of acceleration.

However, solving a non-constant acceleration problem requires integral calculus so I'll just assume the acceleration is constant. Start with the equation

X+=+%281%2F2%29%28at%5E2%29+%2B+v%5B0%5Dt+%2B+x%5B0%5D (assume x%5B0%5D+=+0.

Now, we have to do a ton of unit conversions. We have

40+mi%2Fhr+=+58.667 ft/s
70+mi%2Fhr+=+102.667 ft/s
DELTA%28v%29+=+30+mi%2Fhr+=+44 ft/s

(you can attain these by multiplying by (1 hr)/(60 min), (1 min)/(60 s), (5280 ft)/(1 mi))

Since acceleration equals 44%2F9.8+=+4.49 ft/s^2 we can plug in a, v[0], t.

X+=+%281%2F2%29%284.49%2A9.8%5E2%29+%2B+40%289.8%29+=+607.6 ft (I left out the units that occur with decimals since they create problems parsing the data on this site. The units have to be consistent anyway, it's also easy to show that is true).

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The average speed for the 9.8 seconds is 55 mph (40 + 70)/2
55 mph = 55*22/15 ft/sec = 242/3 ft/sec
242/3 * 9.8 =~ 790.533 feet