Calculating Error in Horizontal Velocity for Bouncing Ball Experiment

In summary, the conversation discusses finding the equation for calculating the error in the horizontal component of a ball's velocity when it bounces off a ramp and hits the ground. The possible solutions given involve the measured variables and partial derivatives. However, none of the options seem correct and the 2 in 2h is not significant. What matters is the powers of the variables and the product rule of differentiation.
  • #1
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Homework Statement


I slide a ball off of a ramp (the ramp is on a table) and the ball hits the ground and bounces horizontally and vertical.
I know that horizontal velocity = horizontal distance*sqrt(gravity/2*height) or d*sqrt(g/2h)
I want to know the equation for calculation error.

The expression for the error in the horizontal component of ball's velocity is:
Select one:
a. error v = v[(error d)/d + (error g)/g +(error h)/h]
b. error v/2 = v[(error d)/d + (error g)/g +(error h)/h]
c. error v/4 = v[(error d)/d + (error g)/g +(error 2h)/h]
d. error v = v[(error d)/d + (error g)/g +(error 2h)/h]
e. error v/2 = v[(error 2d)/d + (error g)/g +(error h)/h]


Homework Equations





The Attempt at a Solution


I think its a. The problem I have is the 2h. I don't know how to deal with it. If v=sqrt(g/h) then I know for sure the answer is a. but since that 2 is there I don't know if the answer is still a.
 
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  • #2
If [itex]x[/itex] is a function of measured variables [itex]u, v, \ldots[/itex],
[tex]x = f(u, v, \ldots),[/tex]
then,
[tex]\sigma_x^2 \approx \sigma_u^2 \left ( \frac{\partial x}{\partial u}
\right )^2 + \sigma_v^2 \left ( \frac{\partial x}{\partial v} \right )^2
+ \ldots \;.[/tex]
You should be able to figure it out from there. Except that I think you may have written down the possible solutions incorrectly; aren't there some missing square roots?
 
  • #3
None of the choices seem right to me.
Don't worry about the 2 in the 2h. That's just a factor of root 2 on the whole expression. It has no relationship to the h specifically. What matters is the powers of the variables. If e.g. z = A xmyn then Δz/z = m Δx/x + n Δy/y. It's just the normal product rule of differentiation.
 

Related to Calculating Error in Horizontal Velocity for Bouncing Ball Experiment

What is propagation of error?

Propagation of error is a mathematical method used to determine the uncertainty in the result of a calculation that involves multiple variables with their own uncertainties.

Why is propagation of error important?

Propagation of error is important because it allows scientists to quantify the uncertainty in their measurements and calculations, which is crucial for accurate and reliable results in scientific research.

How is propagation of error calculated?

Propagation of error is calculated by using the standard deviation of each variable and the partial derivatives of the function being evaluated. These values are then combined using the root sum square method to determine the overall uncertainty in the final result.

What are some common sources of error in scientific experiments?

Some common sources of error in scientific experiments include instrument limitations, human error, environmental factors, and sampling error. These can all contribute to the uncertainty in measurements and calculations.

How can propagation of error be minimized?

Propagation of error can be minimized by using precise and accurate instruments, minimizing human error through proper training and procedures, and controlling environmental factors. Additionally, increasing sample size and conducting multiple trials can also help reduce the overall uncertainty in a calculation.

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