Speed is like an element from science. I don’t know much about speed but I tell you everything I know.

Speed can do so many things. Speed has 2 parts, velocity and acceleration.

Part 1 Velocity

For over a thousand years, people known as our ancestors have been studying about speed for a very long time. Not much people know the formula for increased speed. Speed is all around us. In fact you use it everyday whether you’re cooking or sleeping, or working or playing. Speed is always around us and we can’t escape it. However, I will tell you the first part about speed. That part is Velocity. Velocity measures how fast and object is moving or as we call it, rate. The velocity of an object is the rate of change of its position with respect to a frame of reference and is a function of time. Velocity is reduced when your speed and position change or redirect to another location. Without velocity, you wouldn’t be moving fast.

Part 2 Acceleration

Acceleration is applied when you want to go a lot faster. Acceleration is the rate of change on velocity. For example, when a car starts from a standstill (zero relative velocity) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the car turns, there is an acceleration toward the new direction. In this example, we can call the forward acceleration of the car a “linear acceleration”, which passengers in the car might experience as a force pushing them back into their seats. When changing direction, we might call this “non-linear acceleration”, which passengers might experience as a sideways force. If the speed of the car decreases, this is an acceleration in the opposite direction from the direction of the vehicle, sometimes called deceleration**.** Passengers may experience deceleration as a force lifting them forwards. Mathematically, there is no separate formula for deceleration: both are changes in velocity. Each of these accelerations (linear, non-linear, deceleration) might be felt by passengers until their velocity (speed and direction) matches that of the car. There’s are 3 types of speed, Instantaneous Speed, Average Speed and Tangential Speed.

Part 3 Instantaneous Speed

Speed at some instant, or assumed constant during a very short period of time, is called *instantaneous speed*. By looking at a speedometer, one can read the instantaneous speed of a car at any instant. A car travelling at 50 km/h generally goes for less than one hour at a constant speed, but if it did go at that speed for a full hour, it would travel 50 km. If the vehicle continued at that speed for half an hour, it would cover half that distance (25 km). If it continued for only one minute, it would cover about 833 m

Part 4 Average Speed

Different from instantaneous speed, *average speed* is defined as the total distance covered divided by the time interval. For example, if a distance of 80 kilometres is driven in 1 hour, the average speed is 80 kilometres per hour. Likewise, if 320 kilometres are travelled in 4 hours, the average speed is also 80 kilometres per hour. When a distance in kilometres (km) is divided by a time in hours (h), the result is in kilometres per hour (km/h). Average speed does not describe the speed variations that may have taken place during shorter time intervals (as it is the entire distance covered divided by the total time of travel), and so average speed is often quite different from a value of instantaneous speed. If the average speed and the time of travel are known, the distance travelled can be calculated by rearranging the definition to

d=vt

Using this equation for an average speed of 80 kilometres per hour on a 4-hour trip, the distance covered is found to be 320 kilometres.

Expressed in graphical language, the slope of a tangent line at any point of a distance-time graph is the instantaneous speed at this point, while the slope of a chord line of the same graph is the average speed during the time interval covered by the chord.

Part 5 Tangential Speed

Linear speed is the distance travelled per unit of time, while tangential speed (or tangential velocity) is the linear speed of something moving along a circular path. A point on the outside edge of a merry-go-round or turnable travels a greater distance in one complete rotation than a point nearer the center. Travelling a greater distance in the same time means a greater speed, and so linear speed is greater on the outer edge of a rotating object than it is closer to the axis. This speed along a circular path is known as *tangential speed* because the direction of motion is tangent to the circumference of the circle. For circular motion, the terms linear speed and tangential speed are used interchangeably, and both use units of m/s, km/h, and others.

Rational Speed (or *angular speed*) involves the number of revolutions per unit of time. All parts of a rigid merry-go-round or turntable turn about the axis of rotation in the same amount of time. Thus, all parts share the same rate of rotation, or the same number of rotations or revolutions per unit of time. It is common to express rotational rates in revolutions per minute (RPM) or in terms of the number of “radians” turned in a unit of time. There are little more than 6 radians in a full rotation (2πradians exactly). When a direction is assigned to rotational speed, it is known as rotational velocity or angular velocity. Rotational velocity is a vector whose magnitude is the rotational speed.

Tangential speed and rotational speed are related: the greater the RPMs, the larger the speed in metres per second. Tangential speed is directly proportional to rotational speed at any fixed distance from the axis of rotation. However, tangential speed, unlike rotational speed, depends on radial distance (the distance from the axis). For a platform rotating with a fixed rotational speed, the tangential speed in the centre is zero. Towards the edge of the platform the tangential speed increases proportional to the distance from the axis.

where *v* is tangential speed and ω (Greek letter omega) is rotational speed. One moves faster if the rate of rotation increases (a larger value for ω), and one also moves faster if movement farther from the axis occurs (a larger value for *r*). Move twice as far from the rotational axis at the centre and you move twice as fast. Move out three times as far and you have three times as much tangential speed. In any kind of rotating system, tangential speed depends on how far you are from the axis of rotation.

When proper units are used for tangential speed *v*, rotational speed ω, and radial distance *r*, the direct proportion of *v* to both *r* and ω becomes the exact equation

Thus, tangential speed will be directly proportional to *r* when all parts of a system simultaneously have the same ω, as for a wheel, disk, or rigid wand.