A verb that means to increase velocity.
As a simple verb, to accelerate is to increase in speed or to move at a quicker pace. This term is usually used when referring to vehicles, particularly cars and motorcycles. Acceleration is a key concept in physics, too, defined as a change in velocity. It's measured in meters per second squared (m/s2)
Acceleration almost always denotes an increase in speed. Even if you are not a physicist, and a car goes by at a constant speed, you wouldn't say that it “accelerated past you,” despite the fact that it was likely the driver was holding their foot down on the accelerator pedal. Anything which can travel can also accelerate, from a particle to a jumbo jet.
In physics, acceleration is known as a change in velocity because it can have a negative value. In terms of explaining this, we should first look at the acceleration equation. The scientific equation for acceleration is as follows:
Acceleration = (Final Velocity – Initial Velocity) / Time
Example of Accelerate
Let's say that you are working on a roller coaster design, and you want to make sure the cars on the track are safely moving faster than any other ride in your theme park. Since roller coasters take time to get up to speed, you'd want to understand the anticipated acceleration of your design at the first hill on the ride.
In your test run, you find out that your cars start at the top of the hill going 10 miles per hour. By the time they reach the giant dinosaur that's ahead down the hill, it's going at a speed of 50 miles per hour. It takes 8 seconds for the cars to reach that speed. What would be the cars' rate of acceleration?
Let's apply the variables and break down the equation:
- x = (50 mph – 10 mph) / 8 seconds
- x = 40 mph / 8 seconds
- x = 5 m/s2
Significance of Accelerate
Looking at the equation, we can see why acceleration can be a positive or negative value. The final velocity does not necessarily need to be higher than the initial velocity for the equation to stand. So in physics, something can “accelerate” from 5 meters per second to 3 meters per second.
Generally, physicists use this equation to support their understanding of how to improve new technologies in machinery like planes and trains. But, surprisingly, it's also used in sports.
Acceleration is key and different from speed. While a player might be able to run at a speed of 15mph in a sprint, the time it takes them to reach this speed is very important, particularly when chases happen over relatively short distances, as in soccer or football.
Acceleration vs Speed
Looking further into this differentiation, we should consider the definition of speed. Speed is the distance traveled over a particular period of time, whereas acceleration is the change in velocity in a given time period. An important point of differentiation between the two concepts is the fact that speed is defined as a scalar quantity while acceleration is a vector quantity.
Unlike scalar quantities, vectors have a direction. Something can only accelerate in a given direction and in a straight line. When a car goes around a corner, it's actually accelerating in multiple directions at once. Speed alone doesn't account for this. You could drive around a racetrack and be given an average speed, but it wouldn't be an accurate representation of your driving experience because you wouldn't understand where and when you had to speed up or slow down.
Because of this, the actual value the acceleration equation gives us is known as magnitude. It's the magnitude of the object’s acceleration in a given direction. These are other vector quantities measured in this way:
All of the above behave in the same way as acceleration: they only exist in a given direction.