What is a Measure of How Velocity is Changing With Time?
The measure of how velocity is changing with time is called acceleration.
As defined, the rate at which velocity changes with time is called acceleration. Acceleration is a measure of how quickly the velocity is changing. This means acceleration quantifies how rapidly an object's speed, direction, or both are altering. If velocity does not change, there is no acceleration. An object moving at a constant speed in a straight line has zero acceleration.
What Does Changing Velocity Mean?
Velocity is a vector quantity, possessing both magnitude (speed) and direction. Therefore, a change in velocity, and thus acceleration, can occur in several ways:
- Increasing Speed: An object is speeding up (positive acceleration in the direction of motion).
- Decreasing Speed: An object is slowing down (negative acceleration, often called deceleration, acting opposite to the direction of motion).
- Changing Direction: An object is turning or moving along a curved path (acceleration is directed towards the center of the curve).
Examples of Acceleration in Action
Here are some common examples illustrating acceleration:
- A car merging onto a highway and increasing its speed.
- A train coming to a stop at a station.
- A roller coaster speeding up as it goes down a hill.
- A satellite orbiting the Earth at a constant speed but continuously changing direction.
- An apple falling from a tree, accelerating downwards due to gravity.
In summary, acceleration is the fundamental concept used in physics to describe and quantify any change in an object's velocity over a period of time.
