Question
In a relay race, runner A is carrying a baton and has a speed of 3.0 m/s . When he is 25M behind the starting line, runner B starts from rest and accelerates at .10 m/s^2. How long afterwards will A catch up with B to pass the baton to B?
Answers
distance covered by behind runner: 3*t
distance by starter: 1/2 a t^2
these times have to be equal,
so 3t-25=1/2(.1)t^2
multiply by 20, put in quadratic form
t^2-60t-500=0
t= (30-+ sqrt(3600/4 +500))
= 30 +- 10 sqrt (9+5)
now for an engneering check:
let sqrt (15) appx=4
t=70, or -10 throw out the negative time, we are not going backwards.
Distance covered by runner: 280
distance covered by starter: 4900*.05=appx 250 which sounds like a reasonable answer, as runner has to go 25 m further.
Work it accurately.
distance by starter: 1/2 a t^2
these times have to be equal,
so 3t-25=1/2(.1)t^2
multiply by 20, put in quadratic form
t^2-60t-500=0
t= (30-+ sqrt(3600/4 +500))
= 30 +- 10 sqrt (9+5)
now for an engneering check:
let sqrt (15) appx=4
t=70, or -10 throw out the negative time, we are not going backwards.
Distance covered by runner: 280
distance covered by starter: 4900*.05=appx 250 which sounds like a reasonable answer, as runner has to go 25 m further.
Work it accurately.
Related Questions
A relay race is run along a straight line track 300.0 m long running south to north. 1st runner - s...
My problem:
One runner in a relay race has a 1.50 s lead and is running at a constant speed of 3....
During a rElay race along a straight ROAD the 1st runner on a three person team runs D1 with a cons...
A relay race is 1
3
4
miles long. Each relay team has 4 runners. If each runner runs the same d...