Solution Found!
Consider the nail-firing device of Example 4.15. When the
Chapter 4, Problem 158E(choose chapter or problem)
Consider the nail-firing device of Example 4.15. When the device works, the nail is fired with
velocity, 𝑉, with density
\(f(v)=\frac{v^{3} e^{-v / 500}}{(500)^{4} \Gamma(4)}\).
The device misfires 2% of the time it is used, resulting in a velocity of 0. Find the expected kinetic energy associated with a nail of mass 𝑚. Recall that the kinetic energy, 𝑘, of a mass 𝑚
moving at velocity 𝑣 is \(k=\left(m v^{2}\right) / 2\).
The kinetic energy 𝑘 associated with a mass m moving at velocity 𝑣 is given by the expression
\(k=\frac{m v^{2}}{2}\).
Consider a device that fires a serrated nail into concrete at a mean velocity of 2000 feet per second, where the random velocity 𝑉 possesses a density function given by
\(f(v)=\frac{v^{3} e^{-v / 500}}{(500)^{4} \Gamma(4)}, \quad v \geq 0.\)
Find the expected kinetic energy associated with a nail of mass 𝑚.
\(E(K)=E\left(\frac{m V^{2}}{2}\right)=\frac{m}{2} E\left(V^{2}\right),\)
Equation Transcription:
Text Transcription:
f(v)=v^3e^-v/500 over (500)^4 Gamma(4)
k=(mv^2)/2
k=mv^2 over 2
f(v)=v^3e^-v/500 over (500)^4 Gamma(4), v>/=0
E(K)=E(mV^2 over 2)=m over 2 E(V^2)
Questions & Answers
QUESTION:
Consider the nail-firing device of Example 4.15. When the device works, the nail is fired with
velocity, 𝑉, with density
\(f(v)=\frac{v^{3} e^{-v / 500}}{(500)^{4} \Gamma(4)}\).
The device misfires 2% of the time it is used, resulting in a velocity of 0. Find the expected kinetic energy associated with a nail of mass 𝑚. Recall that the kinetic energy, 𝑘, of a mass 𝑚
moving at velocity 𝑣 is \(k=\left(m v^{2}\right) / 2\).
The kinetic energy 𝑘 associated with a mass m moving at velocity 𝑣 is given by the expression
\(k=\frac{m v^{2}}{2}\).
Consider a device that fires a serrated nail into concrete at a mean velocity of 2000 feet per second, where the random velocity 𝑉 possesses a density function given by
\(f(v)=\frac{v^{3} e^{-v / 500}}{(500)^{4} \Gamma(4)}, \quad v \geq 0.\)
Find the expected kinetic energy associated with a nail of mass 𝑚.
\(E(K)=E\left(\frac{m V^{2}}{2}\right)=\frac{m}{2} E\left(V^{2}\right),\)
Equation Transcription:
Text Transcription:
f(v)=v^3e^-v/500 over (500)^4 Gamma(4)
k=(mv^2)/2
k=mv^2 over 2
f(v)=v^3e^-v/500 over (500)^4 Gamma(4), v>/=0
E(K)=E(mV^2 over 2)=m over 2 E(V^2)
ANSWER:
Solution
Step 1 of 2
We have to find the expected kinetic energy of a nail with mass m
Let K be the kinetic energy
Then
Given that
Here v is following gamma distribution with
The device misfire is 2%
The device fire is 98% that is 0.98
Now E(v2)=
=
=4(5)(500)2
=5000000