Two skiers in opposite directions
Two skiers go in opposite directions, the second a few km/h slower. Find the distance between them after the given time.
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
The second skier's speed is given through the first's: dv km/h less. Change both values and the time and watch the scene adjust.
How to run it
- Run the scene: the two move apart, and the S caption shows the distance between them.
- Enter your answer in the Task panel and press “Check”.
- Change the speeds or the time with the sliders and solve again.
Questions to discuss
- Why are the speeds added when moving in opposite directions too?
- How does the distance change if the time doubles?
The science
Every hour the gap grows by the sum of the speeds: the speed of separation. The distance is S = (v₁ + v₂) · t and the time is t = S / (v₁ + v₂).
Try it at home
Stand back to back with a friend and walk 10 steps each in opposite directions: how many steps apart are you?
What to change in the editor
- In the editor flip one participant to get a same-direction or catch-up problem.
- Add a caption with each participant's distance from the start.