Why can't we apply the speed equation in a free fall?

In summary: These equations take into account the acceleration and initial velocity to give you the velocity at a specific time or position. In summary, when dealing with free fall, the acceleration is constant and therefore the velocity increases over time. While you can use the speed = d/t formula, it will give you the average velocity, not the velocity at a specific point in time or space. To find the velocity at a specific point, you need to use the kinematic equations.
  • #1
axer
35
4
Hello, so i know in a free fall the acceleration is constant (9.8 m/s2) therefore speed/velocity is increasing.. But I am wondering why we can't use Speed=D/T
 
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  • #2
Go back and think about the several points you just made. If velocity is changing, does a formula that gives a single speed over time make sense to you.
 
  • #3
axer said:
Hello, so i know in a free fall the acceleration is constant (9.8 m/s2) therefore speed/velocity is increasing.. But I am wondering why we can't use Speed=D/T

You can and that will give you the average speed.
 
  • #4
axer said:
Hello, so i know in a free fall the acceleration is constant (9.8 m/s2) therefore speed/velocity is increasing.. But I am wondering why we can't use Speed=D/T
You most definitely can use the velocity = d/t formula. Just keep in mind that the speed you will find from this equation will be the average velocity, this means that it is the average of all the velocities combined since you are combining the total distance and total time.

If you want to find the velocity at any given point in time or space, then you need to use the kinematic equations.
 

1. Why can't we apply the speed equation in a free fall?

The speed equation, also known as the kinematic equation, cannot be applied in a free fall because the acceleration of an object in free fall is not constant. In free fall, the acceleration due to gravity is constantly changing as the object falls towards the ground. Therefore, the speed equation, which requires a constant acceleration, cannot accurately calculate the speed of an object in free fall.

2. What equation should be used to calculate speed in a free fall?

The equation for calculating speed in a free fall is v = gt, where v is the final velocity, g is the acceleration due to gravity (9.8 m/s^2), and t is the time the object has been falling. This equation takes into account the changing acceleration of an object in free fall and provides a more accurate calculation of speed.

3. Can the speed equation be applied in any situation?

No, the speed equation can only be applied in situations where the acceleration is constant. This includes scenarios such as an object rolling down an incline or a car traveling at a constant speed. In situations with changing acceleration, such as free fall, the speed equation cannot be used.

4. Is there a way to modify the speed equation to work in a free fall?

Yes, the speed equation can be modified by incorporating the changing acceleration into the equation. This is done by using calculus and creating a new equation, which is v = u + at, where u is the initial velocity. This equation is more complex but can accurately calculate the speed of an object in free fall.

5. Why is it important to understand the limitations of the speed equation?

It is important to understand the limitations of the speed equation because it allows us to accurately apply it in situations where it is appropriate. By understanding that the speed equation cannot be used in a free fall, we can avoid making incorrect calculations and better understand the concepts of acceleration and velocity. It also highlights the need for more advanced equations, such as the one used for free fall, in more complex situations.

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