- The main types of speed
- 1- Constant speed
- 2- Variable speed
- 3- Instantaneous speed
- 4- Terminal velocity
- 5- Average speed
- References
The speed types are constant speed, variable speed, instantaneous speed, terminal, and average. Speed is a term widely used in physics to describe the motion of objects. Speed measures the movement of objects based on their speed and direction.
It is important to know the difference between speed and speed to understand the following concepts. The speed of an object measures the distance it travels during a specific period of time.
Speed is a scalar measure, as it only defines the magnitude of the motion. The velocity, on the other hand, is a vector quantity since it describes both the speed and the direction of the movement.
The main types of speed
1- Constant speed
An object with a constant velocity does not change in speed or direction. The only objects that qualify as moving at a constant speed are those that move in a straight line at a speed that remains continuous.
An object outside of a solar system, in interstellar space, that is not under the influence of external forces could be described as an object moving with a constant speed.
A perfect example would be an asteroid or comet, as long as it is quite far from the effects of Earth's gravity.
Also, if someone is driving on a highway and realizes that it takes equal time intervals to travel from one lamp post to another, this would be an indication that they are traveling at a constant speed.
The formula for determining constant velocity is equal to dividing the displacement by time:
- v - speed in m / s, km / h, etc.
- d - displacement in m, km, etc.
- d - time intervals in s, oh
It can be seen that since the displacement is a positive or negative value, the velocity will have the same directional notation. The similarity in sign for velocity and displacement occurs because the time interval is always positive.
2- Variable speed
Objects with changing speed show changes in speed or direction over a period of time. Changes in the velocity of objects are measured with acceleration.
Objects with a constant velocity and a changing direction are also accelerating. Comets and asteroids within the solar system are examples of objects with changing speed, since their speed or direction is influenced by gravity.
Since this type of speed is the change in speed or direction, it is also considered as acceleration.
Mathematically, acceleration equals the change in velocity divided by a specific amount of time. A car that increases its speed by 10 miles per hour (16 km per hour) every two seconds is accelerating at 5 miles per hour (8 km per hour) every second.
Changes in the direction of an object also constitute acceleration and are usually shown using a graph. Acceleration is not always the result of changes in speed. Acceleration can exist even if the velocity is constant.
This type of acceleration is experienced, for example, when riding a bicycle around a curve. Although you can have a constant speed, the change in direction means that you are accelerating.
3- Instantaneous speed
Instantaneous velocity is a method of determining how quickly an object is changing its speed or direction at a given moment.
Instantaneous velocity is determined by reducing the period of time used to measure acceleration to such a small amount that the object does not accelerate during the given period of time.
This method of measuring speed is useful for producing graphs that measure a series of changes in speed. It is defined as a change in direction and speed at a particular point in time. The changes occur at specific points on a graph.
4- Terminal velocity
Terminal velocity is a term used to describe the motion of an object falling freely through the atmosphere. Objects that fall to the ground in a vacuum will constantly accelerate to the ground.
An object falling through the atmosphere, however, will eventually stop accelerating due to increasing amounts of air resistance.
The point where air resistance equals the acceleration caused by gravity - or any force acting on the object - is known as the terminal velocity.
In other words, it is used to define objects that fall through the atmosphere, which as said are affected by changes in air resistance, so gravity takes over and causes the object to accelerate towards the floor.
5- Average speed
Average speed defines the intermediate speed that an object reaches through a change in position with respect to time.
Therefore, the average speed depends only on the initial position and the final position of the object and does not depend on the path taken by the object to reach the final position from its initial position.
Depending on the path that an object travels, the speed can be of two types: linear speed and angular speed.
- Linear speed: defines the movement of the object in a line.
When driving in a straight line, a linear speed type is presented. Photo recovered from: 8000vueltas.com.
- Angular velocity: defines the movement of the object in the circular direction.
Each gear moves with angular velocity, in opposite directions with respect to the other.
Image via solorobotica.blogspot.com.
Linear velocity is denoted by "v" and angular velocity is denoted by "ω" so the relationship between both velocities is:
V = ωr
Each of the elements of the formula means the following:
- V = linear velocity of the object.
- ω = angular velocity of the object.
- r = radius of curvature along which the object moves.
References
- Thompson, D. (2017). "The Types of Velocity". Recovered from sciencing.com.
- Grant, C. (2012). What are the different types of velocities? About velocity ”. Recovered from enotes.com.
- Gaddy, K. (2013). "What are the three types of changes in velocity?" Recovered from prezi.com.
- Tutor Vista editor team. (2017). Velocity. Recovered from physics.tutorvista.com.
- Elert, G. (2015). "Speed & Velocity". Recovered from physics.info.
- Moe, A. (2015). "Various types of velocity cubes". Recovered from geocap.atlassian.net.
- Resnick, R and Walker, J. (2004). "Fundamentals of Physics, Wiley"; 7th sub-edition.