<u>Answer:</u> The energy gained by the air molecules is 0.011 J.
<u>Explanation:</u>
Law of conservation of energy states that energy can neither be created nor be destroyed but it can only be transformed from one form to another form.
Here, the potential energy of the coffee filter is getting converted into kinetic energy of the coffee filter and some energy is lost by it which is gained by the air molecules in the form of kinetic energy.
So, calculating the potential energy of coffee filter, we use the equation:
P = mgh
where,
m = mass of coffee filter = 1.2 g =
(Conversion used: 1 kg = 1000 g)
g = acceleration due to gravity = ![9.8m/s^2](https://tex.z-dn.net/?f=9.8m%2Fs%5E2)
h = height of coffee filter = 1 m
Putting values in above equation, we get:
![P=1.2\times 10^{-3}kg\times 9.8m/s^2\times 1m\\\\P=1.176\times 10^{-2}J](https://tex.z-dn.net/?f=P%3D1.2%5Ctimes%2010%5E%7B-3%7Dkg%5Ctimes%209.8m%2Fs%5E2%5Ctimes%201m%5C%5C%5C%5CP%3D1.176%5Ctimes%2010%5E%7B-2%7DJ)
- Calculating the kinetic energy of coffee filter, we use the equation:
![E=\frac{1}{2}mv^2](https://tex.z-dn.net/?f=E%3D%5Cfrac%7B1%7D%7B2%7Dmv%5E2)
where,
m = mass of coffee filter = 1.2 g = ![1.2\times 10^{-3}kg](https://tex.z-dn.net/?f=1.2%5Ctimes%2010%5E%7B-3%7Dkg)
v = speed of coffee filter = 0.8 m/s
Putting values in above equation, we get:
![E=\frac{1}{2}\times 1.2\times 10^{-3}kg\times (0.8m/s)^2\\\\E=3.84\times 10^{-4}J](https://tex.z-dn.net/?f=E%3D%5Cfrac%7B1%7D%7B2%7D%5Ctimes%201.2%5Ctimes%2010%5E%7B-3%7Dkg%5Ctimes%20%280.8m%2Fs%29%5E2%5C%5C%5C%5CE%3D3.84%5Ctimes%2010%5E%7B-4%7DJ)
As, energy lost by coffee filter = energy gained by air molecules
So, energy lost by coffee filter = Potential energy - Kinetic energy
Energy lost by coffee filter = ![(1.176\times 10^{-2})-(3.84\times 10^{-4})=0.011J](https://tex.z-dn.net/?f=%281.176%5Ctimes%2010%5E%7B-2%7D%29-%283.84%5Ctimes%2010%5E%7B-4%7D%29%3D0.011J)
Hence, the energy gained by the air molecules is 0.011 J.