A bus and a car toward each other
A bus and a car leave two cities toward each other. Change the distance and speeds with the sliders and check when they meet.
2D
Age 10+10 min
Motion problems
Loading simulation…
Press “Run”. Bodies move by the laws of physics: gravity, friction, elasticity.
What the experiment shows
A bus and a car leave two cities at the same time toward each other. The S caption shows the gap and a rule marks the meeting.
How to run it
- Run the scene and watch the S caption: the distance between them shrinks steadily.
- Enter your answer in the Task panel and press “Check”.
- Move the sliders and solve again: the statement updates itself.
Questions to discuss
- Why are the speeds added when moving toward each other?
- How does the meeting time change if the distance doubles?
The science
Every hour the gap shrinks by the sum of the speeds: the closing speed. The meeting time is the distance divided by the closing speed: t = S / (v₁ + v₂).
Try it at home
Mark two points 20 steps apart on the pavement and walk toward each other with a friend, comparing how many steps each took.
What to change in the editor
- Open the example in the editor and swap the participants for other shapes, changing the speed scale.
- Add a “delay” variable and let one leave later to get a catch-up problem.