What is Angle of Internal Friction(φ)
It is the angle whose tangent (tanφ) is the ratio of frictional resistance along any plane in the soil mass to the component of applied force acting normal to the plane (When Cohesion is Zero). The term tanφ is known as the coefficient of friction.
What is Cohesion
It is the mutual attraction of soil particles due to molecular forces and the presence of moisture films. It depends upon the size of soil particles and the moisture content in the soil mass. Clay is very cohesive whereas sands are almost non-cohesive.
What is Angle of Repose
The natural slope which a soil mass will take during its settlement is called the angle of repose. It depends upon mainly the water content and the type of soil.