An object is said to be moving if it has changed location from one place to another. Therefore this involves distance. Since an object cannot be in two places at the same time, it means that the moving object will take time to move between the two locations. This is regardless of the direction of the resting place from the place of origin. Therefore to describe speed it becomes necessary to factor in the amount of time the moving object takes to travel from one place to another as well as the actual distance between the two places.
A moving object may move at different thrusts between two places and as such it becomes difficult to measure the actual speed at specific time and location during the motion. Therefore it is only possible to get the average speed of a moving body. As such speed (average speed) is termed as the distance travelled divided by the duration take to cover that distance. Thus:
Speed = distance / time
Like most of the quantities in physics, speed has found application in a number of situations. The application of speed has both advantages and disadvantages. Man has applied speed to his own advantage. This quantity has been used very effectively in reducing the amount of time used to accomplish a task. Speed has found ready application in transport as it is now possible to travel great distances on land, water or air over a very short span of time.
More importantly speed has enabled man to travel into outer space to planets such as the moon. In production and manufacturing industry speed has been relevant in reducing the amount of time taken to produce commodities and thus increasing production. In communication technology it is possible to send messages at a super sonic speed to any part of the world.
Therefore speed has not only increased efficiency but also lead to a significant reduction of cost associated with travel, communication and manufacturing. Furthermore the most advantageous quality of speed is that it is not limited to any direction and as such bodies can move to any direction at high speed.
However speed has been disadvantageous to man. Speed has been found to increase the risk of the occurrence of accidents. This is because when a body is in high motion the reaction time is significantly reduced because such a body is highly unstable and thus difficult to control. Thus it increases the probability of an accident happening. For example if two vehicles in high speed and moving in opposite directions along same path meet at a corner, there may not be enough reaction time to prevent the vehicles from colliding.
Furthermore the intensity of the collision increases the magnitude of the accident as a result of the high impact connected with high speed. If such vehicle would have been moving at a slower speed there would have been enough reaction time to prevent them from colliding and subsequently avoid the accident.
As such high speed increases the instability of moving object as well as reducing the reaction time. The combination of instability and reduced reaction time increases significantly the risk and chances of accidents happening.
Thus speed is directly proportional to risk and accidents. Despite this, with caution, speed has been of greater advantage to man. It has been the underlying factor in most of the ground braking human achievements.