Example image of eyePlorer eyePlorer map for 'Four-velocity': Four-vector General relativity Physics Spacetime Special relativity Velocity Inertial frame of reference Event (relativity) Proper time World line Theory of relativity Lorentz transformation Time dilation Chain rule Proper velocity Speed of light Four-acceleration Four-force Four-momentum Calculus Derivative Congruence (general relativity) Asardo Dust (relativity) Fluid solution Relativistic Euler equations Algebra of physical space Dust solution Principle of covariance Nordström's theory of gravitation Covariant formulation of classical electromagnetism Energy condition Scalar theories of gravitation Proper acceleration Stress-energy tensor Moving magnet and conductor problem Mass in special relativity Mathematics of general relativity Lorentz force Alternatives to general relativity