An object resting on a rough surface is attached to a rope at 30 degrees to the horizontal. The rope is pulled with a force of PN. The mass of the object is 5kg.
(A) Draw a diagram showing all the forces acting on the object. Describe the origin of each force using words.
B) By resolving forces in the horizontal and vertical directions, calculate the magnitude of each force in the diagram, giving your answers in terms of P where appropriate.
C) If P=20, the object does not slip. Use this information to give a bound on meu in the form of an equality.
I've got A), B) and almost C.
I've got meu in the last question by resolving vertically to find R and then horizontally(resultant force is 0) to solve meu. I just don't get the inequality sign to use. The mark scheme says meu>=0.44, what's the reason?