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View Full Version : Problem 2.82 You are keeping pace with another runner, at 5minutes per mile, but are


shreecs456_
Jan 30, 2012, 01:35 PM
Problem 2.82
You are keeping pace with another runner, at 5minutes per mile, but are 18 behind her when she is150 from the finish line. (Pace is the reciprocal of speed.)
jagreet singh
Part A
What constant acceleration do you need to catch her at the finish if she maintains a constant speed?
Express your answer using two significant figures.
=

ebaines
Jan 31, 2012, 07:49 AM
The acceleration must be sufficient to allow you to cover the gap in the time it takes the leader to reach the finish line. So:

1/2 a t^2 = d

where d = the gap of 18 (18 what? Feet? Yards? Furlongs?) and t is the time left before she reaches the finish. So t is equal to the distance she has to run of 150 divided by her speed. Solve for a.