A block of mass M is kept on as rough horizontal surface. The coefficient of static frictionbetween the block and the surface is `mu`. The block is to be pulled by applying a force to it. What minimum force is needed to slide the block? In which direction should this force act?

Explanation

To determine the minimum force needed to slide a block of mass \( M \) on a rough horizontal surface with a coefficient of static friction \( \mu \), we can follow these steps:

### Step 1: Understand the Forces Acting on the Block
When a force \( F \) is applied to the block, it can be broken down into two components:
- Horizontal component: \( F \cos \theta \)
- Vertical component: \( F \sin \theta \)

### Step 2: Identify the Normal Force
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