body placed on a rough horizontal level \( W=75 \mathrm{~N} \) horizontal force affected 50 N Makes it about to move en the coefficient of friction equals \( \begin{array}{llll}\text { 1) } \frac{1}{3} & \text { 2) } \frac{2}{3} & \text { 3) } \frac{3}{4} & \text { 4) } \frac{1}{4}\end{array} \)

To find the coefficient of friction (μ), we can use the formula: \[ F_{\text{friction}} = \mu \cdot W \] Where \( F_{\text{friction}} \) is the maximum static friction force before the object moves. Given that the horizontal force is 50 N, we set this equal to the maximum friction force: \[ 50 \, \text{N} = \mu \cdot 75 \, \text{N} \] Solving for μ: \[ \mu = \frac{50 \, \text{N}}{75 \, \text{N}} = \frac{2}{3} \] So the coefficient of friction is \( \frac{2}{3} \), which is option 2! When considering situations like this, it's useful to remember that the coefficient of friction is dimensionless, meaning it simply compares the forces involved in motion without any physical units. It represents the ratio of the force needed to move the object relative to the weight of the object itself. This concept is key in physics, especially in mechanics. Understanding friction is not just limited to dry surfaces; it also applies to various scenarios like ice skating or driving on wet roads. The coefficient of friction can vary widely based on materials and conditions, which is crucial for engineers and designers when calculating safety and efficiency in real-world applications, such as designing brakes in cars or the soles of shoes!