Is there some sort of calculus relationship between these two kinematics equations?

In summary, we discussed the relationship between position and velocity equations, with the latter being the derivative of the former with respect to time. We also looked at the variable nature of velocity and how it can be derived from the position and acceleration equations.
  • #1
tahayassen
270
1
[tex]{ y }_{ f }={ y }_{ i }+{ v }_{ yi }t+\frac { 1 }{ 2 } { a }_{ y }{ t }^{ 2 }\\ { v }_{ yf }={ v }_{ yi }+{ a }_{ y }t[/tex]

It almost looks like the second equation is the derivative of the first equation with respect to time.
 
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  • #2


Exactly. The velocity of an object is simply the time-derivative of its position function.
 
  • #3


Pengwuino said:
Exactly. The velocity of an object is simply the time-derivative of its position function.

Maybe I'm incredibly rusty on my calculus, but isn't the time-derivative of the first equation the following?

[tex]0={ v }_{ yi }+{ a }_{ y }t[/tex]
 
  • #4


##v_{yf}## isn't a constant, it's a variable, more specifically the dependent variable, a function of t. Written as functions, your two equations are

$$y(t) = y_i + v_{yi} t + \frac{1}{2}a_y t^2 \\ v_y(t) = v_{yi} + a_y t$$
 
  • #5


jtbell said:
##v_{yf}## isn't a constant, it's a variable, more specifically the dependent variable, a function of t. Written as functions, your two equations are

$$y(t) = y_i + v_{yi} t + \frac{1}{2}a_y t^2$$

$$v_y(t) = v_{yi} + a_y t$$

Thank you!
 
  • #6
Last edited:

1. What is the difference between the two kinematics equations?

The first kinematics equation, also known as the position equation, describes the relationship between an object's initial position, final position, velocity, and time. The second kinematics equation, also known as the velocity equation, describes the relationship between an object's initial velocity, final velocity, acceleration, and time.

2. Is there a connection between the two equations?

Yes, there is a connection between the two equations. The velocity equation can be derived from the position equation by taking the derivative with respect to time. This means that the two equations are related by the concept of calculus.

3. Can the kinematics equations be used to solve real-world problems?

Yes, the kinematics equations are commonly used in physics and engineering to solve real-world problems involving motion. They can be used to calculate an object's position, velocity, acceleration, and time given certain variables.

4. Are there any limitations to using the kinematics equations?

While the kinematics equations are useful for solving many problems, they do have some limitations. They are based on the assumptions of constant acceleration and no external forces acting on the object, which may not always be true in real-life situations. Also, they are limited to one-dimensional motion and do not account for rotational or circular motion.

5. Can the kinematics equations be applied to any type of motion?

The kinematics equations can be applied to any type of motion as long as the assumptions of constant acceleration and no external forces hold true. This includes linear motion, projectile motion, and motion in a straight line with changing acceleration. However, they cannot be applied to rotational or circular motion.

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