# When is velocity and speed the same.

krishna-agrawala | College Teacher | (Level 3) Valedictorian

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Velocity of an object refers to the rate of movement or change of its position in terms of distance covered as well as the direction of movement. In contrast, speed is a measurement of the rate of change of position. A variable or quantity like velocity that has speed as well as direction is called a vector. A variable or quantity that has only magnitude is called a scalar quantity.

The magnitude of velocity and speed are measured in the same units such as 'meters per second, or 'kilometers per hour'. The magnitude of velocity and the speed of a body is same when the movement of the body is in a straight line, and there is no reversal of direction of movement due to acceleration.

When a object moves along a curved path at a constant speed, the velocity is not constant but variable. For example, an object moving along a circle of radius r at constant speed of x meters per second will have a variable velocity due to an acceleration equal to (x^2)/r m/s^2 acting towards the center of the circle.