How to Recognize Kinematics Equations in Physics
Recognize the variables you will be using., Familiarize yourself with the symbols used to represent movement in these equations., Familiarize yourself with the basic kinematic equations., Look at an example of an equation that is not kinematic, but...
Step-by-Step Guide
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Step 1: Recognize the variables you will be using.
To recognize a kinematic equation, you will need to know the units and variables that will be displayed in the equation.
These include: vf – final velocity vi – initial velocity a – acceleration xf – final position xi – initial position t – time -
Step 2: Familiarize yourself with the symbols used to represent movement in these equations.
There are established kinematic equations that you can learn.
Keep in mind that when looking at kinematic equations, there are certain assumptions you must have.
These include:
Knowing that the object being described as a constant acceleration Using a positive sign to represent horizontal motions going to the right, and vertical motions going upwards.
Using the negative sign for movement to the left or downwards. , It helps to have the following equations memorized so that you can compare other equations, and recognize kinematic equations quickly.Velocity as a function of time: vf = vi + at Position as a function of velocity and time: xf = xi +
0.5(vi + vf)t Position as a function of time: xf = xi + vit +
0.5at2 Velocity as a function of position: vf2 = vi2 + 2a(xf – xi) , For an equation to be considered kinematic, it must contain most or all of the variables listed in the last step of the previous section.
It must also mirror one of the equations listed in the previous step.
Let’s look at an example:
Take a look at: mv1 + F(t2-t1) = mv2 Let’s look at the variables in this equation: m, v, F, and t.
Out of the four, only 2 parameters match those used in kinematic equations.
It also does not mirror any of the forms of the equations; therefore this is not a kinematics equation. , Now let’s look at this example: y = yo + vot
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0.5gt2 The variables used are: y, v, g, and t.
Out of the four, only v and t check out.
But as we can see, this equation is very much similar with equation 3 of step 1 in terms of form.
The variable y, denotes a vertical position, while g denotes gravity.
Gravity has a value of
9.81 m/s2 – and we know that acceleration has a unit of m/s2.
We can classify gravity as acceleration.
However, there is no negative sign in , but still we don’t have minus sign in our equation
3.
But since we know the a vertical displacement increases as we go up, and we also know that gravity pulls downward, we can assess that the negative sign is there to denote that gravity acts on the opposite direction.
So the given equation is indeed a kinematics equation. -
Step 3: Familiarize yourself with the basic kinematic equations.
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Step 4: Look at an example of an equation that is not kinematic
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Step 5: but resembles it.
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Step 6: Look at an example of a kinematic equation.
Detailed Guide
To recognize a kinematic equation, you will need to know the units and variables that will be displayed in the equation.
These include: vf – final velocity vi – initial velocity a – acceleration xf – final position xi – initial position t – time
There are established kinematic equations that you can learn.
Keep in mind that when looking at kinematic equations, there are certain assumptions you must have.
These include:
Knowing that the object being described as a constant acceleration Using a positive sign to represent horizontal motions going to the right, and vertical motions going upwards.
Using the negative sign for movement to the left or downwards. , It helps to have the following equations memorized so that you can compare other equations, and recognize kinematic equations quickly.Velocity as a function of time: vf = vi + at Position as a function of velocity and time: xf = xi +
0.5(vi + vf)t Position as a function of time: xf = xi + vit +
0.5at2 Velocity as a function of position: vf2 = vi2 + 2a(xf – xi) , For an equation to be considered kinematic, it must contain most or all of the variables listed in the last step of the previous section.
It must also mirror one of the equations listed in the previous step.
Let’s look at an example:
Take a look at: mv1 + F(t2-t1) = mv2 Let’s look at the variables in this equation: m, v, F, and t.
Out of the four, only 2 parameters match those used in kinematic equations.
It also does not mirror any of the forms of the equations; therefore this is not a kinematics equation. , Now let’s look at this example: y = yo + vot
-
0.5gt2 The variables used are: y, v, g, and t.
Out of the four, only v and t check out.
But as we can see, this equation is very much similar with equation 3 of step 1 in terms of form.
The variable y, denotes a vertical position, while g denotes gravity.
Gravity has a value of
9.81 m/s2 – and we know that acceleration has a unit of m/s2.
We can classify gravity as acceleration.
However, there is no negative sign in , but still we don’t have minus sign in our equation
3.
But since we know the a vertical displacement increases as we go up, and we also know that gravity pulls downward, we can assess that the negative sign is there to denote that gravity acts on the opposite direction.
So the given equation is indeed a kinematics equation.
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Victoria Henderson
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