Static Friction Calculator

What is Static Friction?

Static friction is the force that prevents two surfaces in contact from sliding against each other when they are not in relative motion. It acts parallel to the surfaces and opposes the impending motion. Static friction is crucial in many everyday situations, from keeping objects at rest on inclined surfaces to allowing us to walk without slipping.

Formula

The formula for static friction force is:

\[ f_s \leq \mu_s N \]

Where:

• \( f_s \) is the static friction force (in Newtons, N)
• \( \mu_s \) is the coefficient of static friction (dimensionless)
• \( N \) is the normal force (in Newtons, N)

The maximum static friction force occurs just before the object starts to move:

\[ f_{s,max} = \mu_s N \]

Calculation Steps

Let's calculate the maximum static friction force for an object on a horizontal surface:

1. Given:
   • Coefficient of static friction (\( \mu_s \)) = 0.5
   • Normal force (\( N \)) = 100 N
2. Apply the maximum static friction formula: \[ f_{s,max} = \mu_s N \]
3. Substitute the known values: \[ f_{s,max} = 0.5 \times 100 \text{ N} \]
4. Perform the calculation: \[ f_{s,max} = 50 \text{ N} \]

Example and Visual Representation

Let's visualize the static friction force for an object on a horizontal surface:

This diagram illustrates:

• The object (green rectangle) resting on a horizontal surface (blue line)
• The normal force (\( N \)) acting upward (red arrow)
• The static friction force (\( f_s \)) acting horizontally (yellow arrow)
• The static friction opposes the impending motion, keeping the object at rest