Factors affecting friction - simulator

FRICTION LABORATORY

Explore the factors affecting friction

Discover how surface roughness, normal force, weight, material, lubrication and contact area influence friction. Perform virtual experiments, observe the forces and calculate the net force acting on an object.

Learning objective: Understand why friction changes under different conditions and predict the motion of objects.

EXPERIMENT INDEX

How to use this laboratory

1. Select an experiment from the index.
2. Change the given controls.
3. Observe the object and force readings.
4. Listen to the audio explanation.
5. Answer the assessment questions.

Remember: Friction opposes relative motion or the tendency of relative motion between surfaces in contact.

Experiment 1: Nature of surfaces

Investigate how the roughness of a surface affects friction.

Choose surface Very smooth glass Smooth wood Rough wood Rough concrete Very rough surface

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→ Push

Normal force: 100 N

Experiment 2: Normal force and load

Place additional weights on a wooden block. Observe how friction changes.

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→

Mass of object: 5 kg

Coefficient of friction: 0.4

Experiment 3: Weight and gravity

Change the mass and gravitational acceleration to investigate weight and normal force.

Mass: 10 kg

Gravity: 9.8 m/s²

Coefficient of friction: 0.3

Experiment 4: Different surface materials

Compare the friction between an object and different surfaces.

Select surface material Ice Polished glass Wood Concrete Rubber on rough surface

Normal force (N)

Experiment 5: Effect of lubrication

Compare the friction between dry and lubricated surfaces.

Normal force: 100 N

Lubrication Dry surface Light lubrication Good lubrication

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Experiment 6: Area of contact

Change the apparent contact area of a rectangular block while keeping its weight and surfaces unchanged.

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Block orientation Larger face on surface Smaller face on surface

Important: In the ideal dry-friction model, friction is approximately independent of apparent contact area. Real materials may behave differently due to deformation, pressure and surface structure.

Experiment 7: Applied force and friction

Gradually increase the force applied to a block. Observe static and kinetic friction.

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Applied force: 0 N

Normal force: 100 N

Experiment 8: Net force calculator

Calculate all the forces acting on an object placed on a horizontal surface.

Mass of object (kg)

Gravitational acceleration (m/s²)

Coefficient of friction

Applied horizontal force (N)

Direction of applied force Towards right Towards left

Friction model Object starts from rest Object is already sliding

Weight = mass × gravity
Normal force = Weight
Maximum static friction = μs × N
Kinetic friction = μk × N
Net force = Sum of all forces

Force diagram

Scientific note: The coefficient supplied here is treated as the static coefficient when the object starts from rest and the kinetic coefficient when it is already sliding. In real materials these coefficients may be different. This calculator assumes a horizontal surface, no vertical applied force and no other forces.

Student assessment

Answer the following questions to test your understanding.

Important scientific conclusions

• Roughness and the nature of contacting materials influence friction.
• Increasing normal force generally increases dry friction.
• Weight affects friction through the normal force on a horizontal surface.
• Lubricants generally reduce friction.
• Apparent contact area has little effect in the ideal Coulomb model.
• Applied force determines whether static friction remains sufficient or sliding begins.
• Net force determines acceleration and direction of acceleration.

Physics Learning Laboratory

Explore • Experiment • Observe • Calculate • Learn