Force & Friction Worksheet
Goal: Find out when friction holds a block still, when it starts to slide, and how net force, mass and acceleration are related (F = ma).
What to do
- Press Reset (5 kg block, 20 N push, μ = 0.3). Record the friction, net force, acceleration and state.
- Press Reset, then “Smooth surface”, and record. Repeat with “Held by friction” and “Sliding”, pressing Reset before each.
- Press Reset and set Applied force to 14 N, then to 15 N. Record both rows.
Record your results
| Setting | Friction | Net force | Acceleration | State |
|---|---|---|---|---|
| Default (5 kg, 20 N, μ = 0.3) | ||||
| Smooth surface (μ = 0) | ||||
| Held by friction (10 N, μ = 0.5) | ||||
| Sliding (60 N, μ = 0.3) | ||||
| 14 N push | ||||
| 15 N push |
Questions
With “Held by friction” the block does not move, even though you push with 10 N. How big is the friction force, and why?
Between 14 N and 15 N the block changes from resting to sliding. Use the maximum friction μN to explain where the switch happens.
Compare the default (μ = 0.3) with “Smooth surface” (μ = 0). How does removing friction change the net force and the acceleration?
Use your “Sliding” row to check Newton’s second law: does net force ÷ mass equal the acceleration?
Predict, then test: if you double the mass to 10 kg and still push with 60 N, will the acceleration be half of the “Sliding” value?
Challenge: this model uses one friction coefficient for both resting and sliding. In real life the kinetic coefficient is usually smaller. What would you notice when pushing a heavy box?
Free from The Physics Lab · thephysicslab.org · MS-PS2-2: Investigate how the change in an object’s motion depends on the sum of the forces on it and its mass. HS-PS2-1: Analyze data to show that Newton’s second law relates net force, mass and acceleration.