Physics is the science that studies motion and matter and how both work with forces and energy. It is a really big subject that has a lot of different “branches” of scientific study that include motion, sound, waves, electricity, light, sound, and even astronomy.
This science covers the tiniest particles and atoms all the way to the largest objects in the universe.Many people get the words speed and velocity confused. While they can be referenced in what we see and do in our lives, they represent two different physics quantities.
When you talk about speed you need to remember that it is the measurement of how fast something is moving as it relates to a point of reference. It doesn’t have a direction like a vector and is therefore called a “magnitude” or “scalar quantity.”
In physics, speed has a formula of: Speed = Distance/Time (or speed is equal to distance divided by time) with the abbreviated version of: s=d/t.
Science measures speed using the standard unit of meters per second or m/s. There are two different types of speed measurements:
Velocity is a bit trickier. It is the rate of change in an object’s position. Velocity has a direction and a magnitude (speed) and it therefore considered to be a vector.
Science uses a formula for velocity of: Velocity = the change in distance/change in time (or Velocity is equal to the change in distance divided by the change in time)
Science uses the same measurement unit of meters per second as they use with speed = m/s.
Let’s say that you were told that someone you knew was driving at 35 kilometers per hour (35 km/hr) but you didn’t know what direction they were going.
You were only given one value so you couldn’t go to a map and draw an arrow line from any point. In this case, physicists would say that the speed is 35 km/hr by the velocity isn’t known.
However, it you were given the information that your friend is driving at 35 km/hr and going north, then you could have an arrow pointing north with a length of 35. Physicist state that the velocity is 35 km/hr north. You now have two values to work with.
Velocity can be defined as the rate of motion in a specific direction. Average speed is the measure of the distance divided by the time that it took. Velocity can be constant or change with acceleration.
In other words, speed with a direction is velocity.
Scientists have defined the fastest possible speed in the universe as the speed of light, which is 299,792,458 meters per second. Physicists represent almost everything with letters and symbols to make things easier to figure out. The number for the speed of light is represented by the letter “c.”
Galileo used mathematics in his discoveries in astronomy and is given credit for being the first scientist to measure speed as distance over time.
What is the definition of speed?
the measurement of how fast something is moving as it relates to a point of reference
What is the definition of velocity?
the rate of motion in a specific direction
Who is given credit for discovering the measurement of speed as distance over time?
What is the fastest speed in the universe?
speed of light
What are the two types of speed?
instantaneous and average
Is an object’s velocity always the same?