Motion in 1D direction, kinematics

[darklich21]

Homework Statement

A jetliner leaves San Franciso for New york, 4600 km away. With a strong tailwind, its speed is 1100 km/hr. At the same time, a s2nd jet leaves New York for San Francisco. Flying into the wind, it makes only 700 km/hr. When and where do the two planes pass each other?

Homework Equations

x=x0 + v0T + 0.5at^2
Vf^2=Vi^2 + 2ad
Vf= Vi + at

The Attempt at a Solution

Basically, from what I know I'm going to make 2 separate sets of equations and somehow equate them, 1 of them in terms of distance, and another one in terms of time. But I don't really know where to start.

the answer was given to me, they'll be at the same point 2.5 hours later @ 2000km. I don't know how to get this. Please help.

 

[Anden]

A hint: How long distance has the planes traveled together when they meet?

 

[rl.bhat]

When the planes meet, duration of flight time must be the same.
In that time interval, one plane has traveled x km and the other (4500 - x ) km.

 

[darklich21]

Well I need to find both the time they meet, and the distance where they meet. But how would I set this up in terms of an equation?

 

[rl.bhat]

Both the planes are moving with uniform velocity. What is the relation between the velocity, time and distance?

 

[darklich21]

D=vt

 

[darklich21]

Im not seeing how that helps me at this point. Doesn't this problem have something to do with equating equations or something of the sort?

 

[darklich21]

I had a bit of a break through, Ok so I found the time at which they will be at the same distance, which was 2.4 hours. I did 4600km/700km/hr= 6.57hr, which is how long the 2nd plane would take to reach the other side, and I also did 4600 km/1100km.hr which is 4.18 hours, which is how long it would take the first plane to reach the other side from where the 2nd plane started.

But how would I find the distance

 

[rl.bhat]

t = x km / (1100 km/h) = (4500 - x) km/( 700 km/h)