A mass of 4 kg rests on a horizontal plane. When the plane is gradually inclined to an angle 0 -15° with the horizontal, the mass just begins to slide. What is the coefficient of static friction between the block and the surface? [Given, tan 15° = 0.2679)

Explanation

To find the coefficient of static friction between the block and the surface when the mass just begins to slide on an inclined plane, we can use the relationship between the angle of inclination and the coefficient of static friction.

### Step-by-Step Solution:

1. **Identify the Given Information:**
- Mass of the block (m) = 4 kg (not directly needed for the calculation of the coefficient of friction).
- Angle of inclination (θ) = 15°.
- Given that tan(15°) = 0.2679.
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