Calculating Time for Two Cars to Meet in Alaska

  • Thread starter Thread starter mikefitz
  • Start date Start date
  • Tags Tags
    Algebra Cars
AI Thread Summary
Two cars, a BMW traveling at 105 km/h and a VW at 43 km/h, are approaching each other on a straight road in Alaska, with an initial distance of 11 km between them. To determine the time until they meet, the combined speed of both vehicles, 148 km/h, is calculated by adding their velocities. Dividing the distance of 11 km by their combined speed yields a time of approximately 268.29 seconds for the cars to meet. The discussion emphasizes visualizing one car as stationary to simplify the problem. The calculation confirms that the approach is correct and leads to the desired result.
mikefitz
Messages
155
Reaction score
0
Two cars are driving toward each other on a straight and level road in Alaska. The BMW is traveling at 105 km/h north and the VW is traveling at 43 km/h south, both velocities measured relative to the road. At a certain instant, the distance between the cars is 11 km. Approximately how long will it take from that instant for the two cars to meet? [Hint: Consider a reference frame in which one of the cars is at rest.]

I'm trying to think of the best way to attack this problem. Wouldn't it make sense to add both vehicles velocities and then figure out how fast they could travel 11km? would that yield the correct answer?
 
Physics news on Phys.org
Yup, that's right :)
 
268.29 seconds is correct, yay!
 
I think what they want you to do is think that the one car is stopped, remove the road and even the Earth from the mental picture. Picture yourself in the car going 43km/h south. If there is nothing around you at all, it could appear that you are stopped, and he is coming at you at 148km/h, right?
 
edit: nevermind. lol, mispost.
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Pigeon Problem Solved: Calculating Car Velocities and Meeting Time
Replies
16
Views
3K
Intro kinematics problem - is this ok?
Replies
5
Views
2K
How Fast Was the Car Moving in the Radar Speed Trap Experiment?
Replies
8
Views
3K
Electric car and battery problem
Replies
12
Views
2K
Calculating Relative Velocity: Train vs. Car Collision
Replies
3
Views
1K
Calculating Time and Acceleration in Constantly Accelerating Cars
Replies
30
Views
10K
Two cars with constant acceleration meeting
Replies
1
Views
2K
Two cars driving toward each other (non-uniform speed)
Replies
5
Views
7K
What Are the Speeds of Two Cars Meeting on a Highway?
Replies
4
Views
2K
Calculating Separation of Cars in a Convoy Moving at Max Speed
Replies
4
Views
3K

Hot Threads

Recent Insights

Back
Top