The sound absorption for wood is greater than the sound absorption coeffiecient for concrete at most frequencies, hence based on the coefficient of absorption for each material, wood is the best choice.
Answer:
a) ![E_{p} = 0](https://tex.z-dn.net/?f=%20E_%7Bp%7D%20%3D%200%20)
![E_{k} = 168.7 J](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%20168.7%20J%20)
![E_{m} = 168.7 J](https://tex.z-dn.net/?f=%20E_%7Bm%7D%20%3D%20168.7%20J%20)
b) ![E_{p} = 73.6 J](https://tex.z-dn.net/?f=%20E_%7Bp%7D%20%3D%2073.6%20J%20)
![E_{k} = 95.8 J](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%2095.8%20J%20)
c)
![E_{k} = 0](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%200%20)
Explanation:
We have:
m: is the ball's mass = 1.5 kg
v₀: is the initial speed = 15 m/s
g: is the gravity acceleration = 9.81 m/s²
a) In the initial position we have:
h: is the height = 0
The potential energy is given by:
![E_{p} = mgh = 0](https://tex.z-dn.net/?f=%20E_%7Bp%7D%20%3D%20mgh%20%3D%200%20)
The kinetic energy is:
![E_{k} = \frac{1}{2}mv^{2} = \frac{1}{2}*1.5*(15)^{2} = 168.7 J](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7Dmv%5E%7B2%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D%2A1.5%2A%2815%29%5E%7B2%7D%20%3D%20168.7%20J%20)
And the mechanical energies:
![E_{m} = E_{p} + E_{k} = 0 + 168.7 J = 168.7 J](https://tex.z-dn.net/?f=%20E_%7Bm%7D%20%3D%20E_%7Bp%7D%20%2B%20E_%7Bk%7D%20%3D%200%20%2B%20168.7%20J%20%3D%20168.7%20J%20)
b) At 5 m above the initial position we have:
h = 5 m
The potential energy is:
![E_{p} = mgh = 1.5*9.81*5 = 73.6 J](https://tex.z-dn.net/?f=%20E_%7Bp%7D%20%3D%20mgh%20%3D%201.5%2A9.81%2A5%20%3D%2073.6%20J%20)
Now, to find the kinetic energy we need to calculate the speed at 5 m:
![v_{f}^{2} = v_{0}^{2} - 2gh = (15)^{2} - 2*9.81*5 = 126.9](https://tex.z-dn.net/?f=%20v_%7Bf%7D%5E%7B2%7D%20%3D%20v_%7B0%7D%5E%7B2%7D%20-%202gh%20%3D%20%2815%29%5E%7B2%7D%20-%202%2A9.81%2A5%20%3D%20126.9%20)
![v_{f} = \sqrt{126.9} = 11.3 m/s](https://tex.z-dn.net/?f=%20v_%7Bf%7D%20%3D%20%5Csqrt%7B126.9%7D%20%3D%2011.3%20m%2Fs%20)
![E_{k} = \frac{1}{2}mv^{2} = \frac{1}{2}*1.5*(11.3)^{2} = 95.8 J](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7Dmv%5E%7B2%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D%2A1.5%2A%2811.3%29%5E%7B2%7D%20%3D%2095.8%20J%20)
And the mechanical energies:
c) At its maximum height:
: is the final speed = 0
![h = \frac{v_{0}^{2}}{2g} = \frac{(15)^{2}}{2*9.81} = 11.5 m](https://tex.z-dn.net/?f=%20h%20%3D%20%5Cfrac%7Bv_%7B0%7D%5E%7B2%7D%7D%7B2g%7D%20%3D%20%5Cfrac%7B%2815%29%5E%7B2%7D%7D%7B2%2A9.81%7D%20%3D%2011.5%20m%20)
Now, the potential, kinetic and mechanical energies are:
![E_{k} = \frac{1}{2}mv^{2} = 0](https://tex.z-dn.net/?f=%20E_%7Bk%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7Dmv%5E%7B2%7D%20%3D%200%20)
I hope it helps you!
the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.
It is referred to as humidity. Hope I helped!
Answer:
L = L0 (1 + c T) where c is the coefficient and T the change in temperature
L = 50 ( 1 + 2.05E-6 * 50) = 50.0051 cm