Write the nature of forces involved in the following cases.
A cylinder is rolling on the ground.

Explanation

To determine the nature of forces involved when a cylinder is rolling on the ground, we will analyze the situation step by step.

### Step 1: Identify the type of forces
Forces can be classified into two categories: contact forces and non-contact forces.

### Step 2: Identify contact forces
When a cylinder rolls on the ground, there is a contact force acting between the cylinder and the ground. The primary contact force in this case is:

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