The relativistic version of this quantity is tangent to the world line. For a modulated wave, "omega over k" and "d omega dk" give its phase and group forms, respectively. The magnetic force on a charged particle is proportional to "[this quantity] cross B." "Square root of 
The relativistic version of this quantity is tangent to the world line. For a modulated wave, "omega over k" and "d omega dk" give its phase and group forms, respectively. The magnetic force on a charged particle is proportional to "[this quantity] cross B." "Square root of 2 g R" is the minimum magnitude of this quantity needed to escape Earth's orbit, and its vertical component is zero at the highest point of projectile motion. Its rate of change is acceleration, and it is defined as the derivative of position. For 10 points, name this vector quantity whose magnitude is speed.
The relativistic version of this quantity is tangent to the world line.
velocity [prompt on "v"; do not accept "speed"] 