A scalar will be a quantity that has a magnitude but no direction. Scalars can be negative, depending on the scale. For example, it can be -20 degrees Celsius, which is because of the scale that determines temperature. There is no arrow in a scalar quantity. Distance and speed are scalars; however, velocity and displacement are vectors. In order to describe the direction of a specific vector, there must be a coordinate system. In one dimension, the coordinate system is a line that starts from the left and ends on the left, usually a number that is along the x-axis. Movement to the right is positive, while movement to the left is negative. If using an up and down motion, movement upward is positive and movement downward is negative. This is done on the y-axis. Sometimes, with falling objects, movement downward is considered positive. In reality, it doesn’t matter which direction is positive as long as you define this clearly. If not defined, use the x-axis and y-axis as is seen in mathematics to define movement in one direction.
VELOCITY AND ACCELERATION Velocity and acceleration take time into consideration. Time, in physics, represents change or an interval in which change occurs. It cannot be possible to know that time has passed unless something changes during that time. As mentioned, the SI unit for time is the second, with the change being a certain number of units per second. As mentioned, something should change if time is a factor. There can be the length of a certain event, beginning at noon and ending at 12:30 pm. In such cases, the elapsed time is 30 minutes (note that the use of seconds here would be inappropriate). As time moves forward, this will always be a positive number and is therefore a scalar and not a vector. The delta symbol is used to represent the change in time (or delta-t). For simplicity’s sake, motion is said to start at time zero so that there is no definite need to use the delta-t designation and just “t” is used to represent time. Velocity is the displacement of something over time. It can be listed in miles per hour or kilometers per hour. In SI units, velocity will be in meters per second. The average velocity is the displacement divided by time. This is a vector because displacement is a vector so it can be a negative number. If the object moved -4 meters relative to the initial
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