Salient features of centripetal and centrifugal forces. 

Centripetal Force:

• It is a real force which is exerted on the body by the external agencies like gravitational force, tension in the string, normal force etc. 
• Acts in both inertial and non-inertial frames 
• It acts towards the axis of rotation or center of the circle in circular motion

\(|\vec F_{CP}|\) = mω²r = \(\frac{mv^2}{r}\)

• Real force and has real effects 
• Origin of centripetal force is interaction between two objects. 
• In inertial frames centripetal force has to be included when free body diagrams are drawn.

 Centrifugal Force:

• It is a pseudo force or fictitious force which cannot arise from gravitational force, tension force, normal force etc.
• Acts only in rotating frames (non-inertial frame) 
• It acts outwards from the axis of rotation or radially outwards from the center of the circular motion

 \(|\vec I_{Cf}|\) = mω² r = \(\frac{mv^2}{r}\)

• Pseudo force but has real effects 
• Origin of centrifugal force is inertia. It does not arise from interaction. In an inertial frame the object’s inertial motion appears as centrifugal force in the rotating frame. In inertial frames there is no centrifugal force. 
• In rotating frames, both centripetal and centrifugal force have to be included when free body diagrams are drawn.