motion app

What does acceleration mean?
Compared to displacement and velocity, acceleration is like the angry, fire-breathing dragon of motion variables.
It can be violent; some people are scared of it; and if it's big, it forces you to take notice.
That feeling you get when you're sitting in a plane during take-off, or slamming on the brakes in a car, or turning a corner at a high speed in a go kart are all situations where you are accelerating.
Acceleration is the name we give to any process where the velocity changes.
Since velocity is a speed and a direction, there are only two ways for you to accelerate: change your speed or change your directionor change both.
a, equals, start fraction, delta, v, divided by, delta, t, end fraction, equals, start fraction, v, start subscript, f, end subscript, minus, v, start subscript, i, end subscript, divided by, delta, t, end fraction
The above equation says that the acceleration, aaa, is equal to the difference between the initial and final velocities, v_f - v_iv fv i
v, start subscript, f, end subscript, minus, v, start subscript, i, end subscript, divided by the time, \Delta ttdelta, t, it took for the velocity to change from v_iv i
v, start subscript, i, end subscript to v_fv f
v, start subscript, f, end subscript.
[Really?]
Note that the units for acceleration are \dfrac{\text m/s}{\text s}
sm/s
start fraction, start text, m, end text, slash, s, divided by, start text, s, end text, end fraction , which can also be written as \dfrac{\text m}{\text s^2} s 2m
start fraction, start text, m, end text, divided by, start text, s, end text, squared, end fraction.
That's because acceleration is telling you the number of meters per second by which the velocity is changing, during every second.
Keep in mind that if you solve \Large{a= \frac {v_f-v_i}{\Delta t}}a=
tv fv i
equals, start fraction, v, start subscript, f, end subscript, minus, v, start subscript, i, end subscript, divided by, delta, t, end fraction for v_fv f
v, start subscript, f, end subscript, you get a rearranged version of this formula thats really useful.
v_f=v_i+a\Delta tv f =v i
+atv, start subscript, f, end subscript, equals, v, start subscript, i, end subscript, plus, a, delta, t
This rearranged version of the formula lets you find the final velocity, v_fv f
v, start subscript, f, end subscript, after a time, \Delta ttdelta, t, of constant acceleration.
What's confusing about acceleration?
I have to warn you that acceleration is one of the first really tricky ideas in physics.
The problem isnt that people lack an intuition about acceleration.
Many people do have an intuition about acceleration, which unfortunately happens to be wrong much of the time.
As Mark Twain said, It aint what you dont know that gets you into trouble.
Its what you know for sure that just aint so.
The incorrect intuition usually goes a little something like this: Acceleration and velocity are basically the same thing, right? Wrong.
People often erroneously think that if the velocity of an object is large, then the acceleration must also be large.
Or they think that if the velocity of an object is small, it means that acceleration must be small.
But that just aint so.
The value of the velocity at a given moment does not determine the acceleration.
In other words, I can be changing my velocity at a high rate regardless of whether I'm currently moving slow or fast.
To help convince yourself that the magnitude of the velocity does not determine the acceleration, try figuring out the one category in the following chart that would describe each scenario.

Page navigation:

• < Prev
• Next >