Forces & Friction Simulator
Push a block and explore Newton's laws, static and kinetic friction.
Grab the top book and rub it back and forth on the bottom book. The magnified view shows the atoms of both surfaces jiggling more as they warm up. Watch the temperature rise, then let the books cool down.
About the Forces & Friction Simulator
Free forces and motion simulator. Apply a force to a block, change mass and friction, and see net force, acceleration and velocity. Learn Newton's second law and static vs kinetic friction. Built for physics, the forces & friction simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Push a block and explore Newton's laws, static and kinetic friction. Use it to explore physics ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Forces & Friction Simulator
- Use the controls to change Pressing force (weight of book), Surfaces, Magnifier. The simulation reacts instantly.
- Pick an option such as Paper, Wood, Rubber, Ice to switch modes or load an example.
- Press "Cool down" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Push gently and see static friction hold the block.
- Increase the force until it slips, then reduce it.
- Change the surface friction and repeat.
- Drag and flick the block.
Key ideas you can learn
- Newton's second law: net force = mass × acceleration.
- Static friction stops the block from moving until the push exceeds μs × m × g.
- Once moving, kinetic friction (μk × m × g) opposes the motion and is usually smaller.
Where this is used in the real world
Friction decides how brakes, tyres, shoes and conveyor belts work. Engineers use Newton's second law to design safe vehicles and machines.
Who is this simulation for?
Physics students in middle school, high school and first-year university, teachers who want a quick demonstration for the projector, and anyone revising for exams. It works well for flipped classrooms because students can explore before the lesson.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why is it harder to start an object moving than to keep it moving?
Static friction is usually stronger than kinetic friction, so you need a larger force to start motion than to keep it going.
Does mass change the friction force?
Yes. Friction is μ × normal force, and on a flat surface the normal force is m × g, so a heavier block has more friction.
Is the Forces & Friction Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Forces & Friction Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.