# A block weighing 4 kg is on a plane with an incline of (2pi)/3 and friction coefficient of 4/5. How much force, if any, is necessary to keep the block from sliding down?

An incline of $\frac{2 \pi}{3}$ radians is ${120}^{o}$ and therefore the object would not slide down the slope but rather fall of it because it would be upside down!