What is the angle between frictional force and instantaneous velocity of the body moving over a rough surface ?

Explanation

To determine the angle between the frictional force and the instantaneous velocity of a body moving over a rough surface, we can follow these steps:

### Step 1: Understand the Motion of the Body
- When a body moves over a rough surface, it experiences friction. The direction of the body's instantaneous velocity is the direction in which it is moving at that moment.

### Step 2: Identify the Direction of Frictional Force
- The frictional force always acts in the direction opposite to the motion of the body. This is a fundamental property of friction: it opposes the relative motion between surfaces in contact.

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