Worked Example | Where Will Two Cars Traveling at Different Velocities Meet? | Kinematic Equations

At t=0 car traveling at a constant velocity of 25m/s is 100m behind a car traveling in the same direction at a velocity of 20m/s. Calculate the time and position at which the faster car will overtake the slower car.

This problem can be viewed as a relative motion problem where the difference in the velocities between the two vehicles can used to find how long it will take the faster car to make up the difference in the two cars positions... However, while that may work in this case, it is better to learn the fundamentals of setting two equations of motion, more specifically position, equal to each other now in a relatively simple problem. That way later on in more complicated problems you have the skillset to find where two objects undergoing more complicated motion will meet.

This kinematics problem shows up in a variety of STEM courses including high school physics. It serves as the foundation of problems that will appear on the AP Physics 1, AP Physics C, A Level Physics and JEE exams.

[skouterr]

Useful video!! My teacher always tell me to learn the hard way, so in exam that wouldn’t be easy as that.

[meghashyam_nagiri_]

Great Way of Explation and Moreover That Presentation is just Awesome !

[nicolabombace]

You just hinted at it, but you could have solved the time used to catch up using a reference frame moving with the blue car, and solve for the red car to move 100 mt

[cyphex]

helpful video but if you're someone who's fairly comfortable with physics, using relative velocity makes this much simpler.

Relative velocity of car 1 wrt car 2 = 25-20=5 m/s.
Distance to cover = 100m
time taken = 100/5 = 20secs
Distance travelled by car 1 = 25x20 = 500m.

[marshalljamieson]

How would you modify the equation if the time is staggered?

[shinieabrasado]

Why is it 5t=100? I didn't understand that part. (I try using
the formula since i have another problem that involves acceleration and deceleration). Hope you can explain it to me.

[andreanludvig]

I have a physics test on Friday let's Hope this helps otherwise I'm getting kicked from school 😭😭😭😭

[partiquebecois]

The Question is way too simple, will never get this question on an exam

[Studyacoount-bhhc]

U can solve it within 5 seconds in your brain. Relative velocity is 25-29=5 m/s and distance between them is 100. So time taken is relative velocity/ time = 100/5 = 20 secs

[PrinceJafri-rjth]

Such question which you all consider hard problem, this question in our area anyone can solve in our india even those who tend buffalow 😅😅😅

[PrinceJafri-rjth]

25-20=5
t=100/5=20 second
😅😅😅😅😅😅😅Such question which you all consider hard problem, this question in our area anyone can solve in our india even those who tend buffalow 😅😅😅