Difference between Speed and Velocity

Speed and velocity are terms that, although they can function as synonyms in certain contexts, they do not always mean the same thing or are not interchangeable. However,the terms speed and velocity are used synonymously to refer to the distance traveled and the time taken to cover it. However, not in all cases they can refer to the same thing. In didactic subjects such as Physics, they are placed with a different function, then we explain them.

Speed ​​is usually used more with the sense of physical magnitude, or variation per unit of time of a phenomenon or thing, while velocity is used more with the meaning of accelerated movement, or lightness or speed in movement.

What is speed?

It is a physical quantity that indicates the relationship between the distance traveled by an object and the time it used to do so. Kilometers, meters, knots or miles, per hour or per second are used to measure.

In this sense, speed has the same dimension as speed (distance and time), but not in its vector character. That is why speed is a scalar quantity and speed is not.

What is Velocity?

Like speed, velocity is a physical quantity. Only that it expresses the relationship between the space traveled by an object, the time used for it and its direction.

Since it is a quantity that manages to determine the direction of the displacement, velocity is considered a vector quantity, unlike speed, which does not take direction into account and therefore only becomes scalar.

Velocity​​can be measured in meters per second and includes direction.

So, Velocity being a coherent derived unit whose quantity is measured in the SI (metric system) as metres per second (m/s) or as the SI base unit of (m⋅s−1). In this sense, for an object to have a constant speed, it must go in one direction constantly for a specific time. Any change in direction can cause speed to vary.

Examples of Speed And Velocity

An example to better understand the difference between speed and velocity would be the following: if an object is traveling in a straight line north at 100 kilometers per hour for one hour, it will have a speed of 100 km/h north.

On the other hand, if instead of going north it follows a circular path at 100 km/h for an hour, ending at the same point where it started, then we will say that its speed has been zero, even though its speed has been 100 km/h.

The speed, then, would be the scalar absolute value of the speed. In this sense, if there is no direction or heading, we will be talking about speed, while, if a direction is followed, then it will be about speed.

Main Differences between Speed and Velocity

Speed ​​is considered a scalar quantity, but velocity is a vector quantity.

Speed ​​is considered a rate of rhythm in which a certain object covers a distance, while Velocity is the change in position of an object.

In speed the object can change direction and still its average speed will still count. While the velocity of the object must follow a constant direction, if the direction chan8ges, so does the velocity.

The classic formula for determining velocity is:  v = Δs/Δtwhere the V  with the line above it is the average velocity,  Δ r  is the displacement and  Δt  is the time.

The classic formula for calculating speed is  V = d / t.

In other words, the difference between the two concepts lies in the type of magnitude they represent. Speed ​​is scalar magnitude. Velocity is vector magnitude. And what is that in common and ordinary language? Simple! The speed represents a distance traveled in a given time. Speed ​​is the same but takes into account DIRECTION. That is, the speed can be positive, 0 or even negative depending on the direction in which the movement is made.

So, Speed ​​tells us how fast an object is moving, while velocity tells us how fast an object is moving and in what direction and direction.

When To Use Velocity

Velocity is a physical quantity that describes the relationship between the distance traveled and the time used for it, as well as the variation in the characteristics of a phenomenon per unit of time. Likewise, it can refer to the lightness and promptness in the movement, or, in automotive mechanics, to each of the driving positions, also called gait.

For example:

Do you know how fast he was going on this road?

The velocity of global warming has increased.

The boy runs with great velocity.

He put in fifth gear and hit the highway.

In physics, however, velocity is a physical quantity of a vector nature, since it expresses the relationship between the space traveled by an object, the time used for it and its direction.

For example:

The car travels down a road at a constant velocity.

They asked me to determine the velocity with which the ball was thrown.

When To Use Speed

Speed refers to the accelerated movement of something, as well as the quality of fastness. The word, as such, derives from fast.

For example:

I need you to come here quickly.

I am impressed by how quickly children are growing now.

In physics, however, speed is a physical magnitude of a scalar nature, which specifically refers to the relationship between the distance traveled by an object and the time taken to cover it. As such, it can be measured in meters, kilometers, miles, knots per hour, or per second.

For example:

I have to determine how fast that ship is moving.

What is the speed with which that train travels?

Speed ​​and Velocity Comparison

SPEED     

  • Scalar magnitude
  • Rate or rhythm at which a
    object covers a distance
  • It does not depend on the direction

VELOCITY

  • Vector magnitude (magnitude + direction)
  • Change of position of an object, that is, speed and direction of movement
  • It depends on the direction

See Also

Center of Mass of Vs. Center of Gravity