Rotational Motion of a Rigid Body: Moment of Inertia

Torque is the vector product

Torque is the vector product of position vector and force: τ = r × F. Its magnitude is τ = rF sinθ, so it is maximum when force is perpendicular to r.

Angular momentum is the vector product

Angular momentum is the vector product of position vector and linear momentum: L = r × p. Its magnitude is L = rp sinθ. It becomes zero if p = 0, r =

A rigid body is one

A rigid body is one in which external force does not produce relative displacement between its particles. Real bodies are not perfectly rigid, but man

Moment of inertia is the resistance

Moment of inertia is the resistance of a body to change in rotational motion about an axis. For particles, I = Σmr², and for continuous bodies, I = ∫r

Radius of gyration k is defined

Radius of gyration k is defined by I = Mk², so k = √(I/M). It is the distance from the axis at which the whole mass may be assumed concentrated to giv