Which quantity is a scalar quantity

Speed is a scalar quantity — it is the rate of change in the distance travelled by an object, while velocity is a vector quantity — it is the speed of an object in a particular direction.

A geostationary satellite is in orbit above Earth. It moves at constant speed but its velocity is constantly changing since its direction is always changing. Scalar and vector quantities A quantity that has magnitude but no particular direction is described as scalar. Scalar quantities Scalar quantities only have magnitude size.

Scalar quantities include: distance speed time power energy Scalar quantities change when their magnitude changes. Mass has magnitude, generally in kilograms, but cannot act in a direction. In contrast, displacement, velocity, force, and momentum must be applied in a given direction. Displacement is the vector equivalent of the scalar quantity distance, and velocity is the vector equivalent of the scalar quantity speed.

Forces must always act in a given direction, and have no scalar equivalent. Similarly, momentum must always be directional. A child skates around the edge of an ice rink and finishes exactly where she started.

If the rink has a radius of , what is the total displacement of the skater? There is a distinct and crucial difference between measuring displacement and measuring distance. Distance is a scalar quantity, which means that it depends on the path taken and is independent of the direction traveled. Distance measures the total length traveled, without any reference to the starting point. In contrast, displacement is a vector quantity. This means that both the magnitude of the length and its direction must be factored into the calculation.

Displacement is essentially the net distance traveled in relation to the starting point, independent of the path traveled. In this question, the skater finishes in exactly the same place that she started.

Without any other information, we can conclude that her displacement is zero. It does not matter what path she took to return to her starting point; she could have taken one step forward and one step back, skated the entire rink seventeen times, or simply jumped and landed.

All of these possibilities would result in zero displacement. Viscosity is the measurement of a "thickness" of a liquid. Molasses, for example, is a more viscous fluid than water is. Vector measurements are defined by a magnitude and a direction. For a liquid to have a measureable "thickness" is logical, but a liquid cannot have a viscosity in a direction. To say that a fluid has a viscosity of East makes no sense. Viscosity is a scalar quantity.

Displacement, force, velocity, and acceleration all have associated directions and are classified as vector quantities. Vector quantities are defined by both the magnitude of the parameter and the direction of action.

In contract, scalar quantities are independent of direction and rely only on the magnitude of the parameter. Mass, distance, time, and brightness are all scalar quantities. This is to say that none of these terms can be applied in a given direction.

It would be illogical to have "three grams west" or "eighteen seconds to the left. Force is always a vector quantity, since the direction of the force matters in defining the parameter.

To calculate the angle we must first find the inverse tangent of :. This angle value is the principal arctan, but it is in the fourth quadrant while our vector is in the second.

Vector has a magnitude of 3. Express in unit vector form. For vector , the magnitude is doubled, but the direction remains the same. The x-coordinate is the magnitude times the cosine of the angle, while the y-coordinate is the magnitude times the sine of the angle.

The resultant vector is:. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

We live in a at least four-dimensional world governed by the passing of time and three space dimensions; up and down, left and right, and back and forth. We observe that there are some quantities and processes in our world that depend on the direction in which they occur, and there are some quantities that do not depend on direction. For example, the volume of an object, the three-dimensional space that an object occupies, does not depend on direction.

If we have a 5 cubic foot block of iron and we move it up and down and then left and right, we still have a 5 cubic foot block of iron. On the other hand, the location , of an object does depend on direction. If we move the 5 cubic foot block 5 miles to the north, the resulting location is very different than if we moved it 5 miles to the east.

Mathematicians and scientists call a quantity which depends on direction a vector quantity. A quantity which does not depend on direction is called a scalar quantity. Vector quantities have two characteristics, a magnitude and a direction.

Scalar quantities have only a magnitude. When comparing two vector quantities of the same type, you have to compare both the magnitude and the direction. For scalars, you only have to compare the magnitude. When doing any mathematical operation on a vector quantity like adding, subtracting, multiplying.. This makes dealing with vector quantities a little more complicated than scalars. On the slide we list some of the physical quantities discussed in the Beginner's Guide to Aeronautics and group them into either vector or scalar quantities.