LearningPhysics one last runner problem

[anglum]

Homework Statement

Runner A is initially 6.0km west of a flagpole and is running with a constant velocity of 8.4km/h east. Runner B is initially 4.3km east of flagpole and is running with a constant velocity of 7.1km/h west

how far are the runners from the flagpole when their paths cross?

The Attempt at a Solution

so again the time for both are the same and the distance apart is 10.3 km
do i solve for t since t is equal for both runners?

 

[learningphysics]

Homework Statement

Runner A is initially 6.0km west of a flagpole and is running with a constant velocity of 8.4km/h east. Runner B is initially 4.3km east of flagpole and is running with a constant velocity of 7.1km/h west

how far are the runners from the flagpole when their paths cross?

The Attempt at a Solution

so again the time for both are the same and the distance apart is 10.3 km
do i solve for t since t is equal for both runners?

Yes, t is equal... how do the distances the two runners travel relate?

 

[anglum]

well since the time is equal then wouldn't the distance of runner A be 1.18309 times more than runner B?

 

[learningphysics]

well since the time is equal then wouldn't the distance of runner A be 1.18309 times more than runner B?

Yes, but you don't really need that relationship... how does the 10.3km come into play here?

 

[anglum]

im not sure how that comes into play since its where do they intersect

 

[learningphysics]

im not sure how that comes into play since its where do they intersect

draw a sketch... they start at 10.3km apart... they run towards each other... draw a line for the path one runner travels... draw a line for the other...

what is the relationship between the length of the two lines?

 

[anglum]

i see that they intersect i just don't know what formula or what i try and solve for to get this problem

 

[learningphysics]

i see that they intersect i just don't know what formula or what i try and solve for to get this problem

Well, I was getting at... the distance traveled by one runner + distance traveled by the other = 10.3 km

 

[anglum]

ahhhhh damn i knew that ... i thought u meant something more complex... its gettin late here and I am bucklin down to finsih this last one

 

[anglum]

so if the Time is equal and the Distance is D of 1 + D of 2 = 10.3 how do i solve for that?

 

[anglum]

do i get 8.4t + 7.1t = 10.3 km?

which give me a time of intersect at .6645 hours?

 

[learningphysics]

do i get 8.4t + 7.1t = 10.3 km?

which give me a time of intersect at .6645 hours?

yup. how far are they from the flagpole.

 

[anglum]

so after that time runner A has gone 5.581935484 km and he was initially 6km away

so he is now .4180645161 km away from the pole

 

[anglum]

AWESOME THAT WAS CORRECT

YOU ARE THE MAN AND A SAVIOR... this should be all my problems until next week... i was workin ahead to avoid them over the weekend

 

[learningphysics]

AWESOME THAT WAS CORRECT

YOU ARE THE MAN AND A SAVIOR... this should be all my problems until next week... i was workin ahead to avoid them over the weekend

cool. no prob.