A coffee filter of mass 1.4 grams dropped from a height of 4 m reaches the ground with a speed of 0.5 m/s. How much kinetic energy did the air molecules gain from the falling coffee filter? Start from the Energy Principle, and choose as the system the coffee filter, the Earth, and the air

Respuesta :

Answer:

Explanation:

mass of coffee filter, m = 1.4 h

height, h = 4 m

velocity, v = 0.5 m/s

The energy conservation

Potential energy of filter = kinetic energy of filter + energy gained by the air molecules

m x g x h = 0.5 x mv² + energy gained by the air molecules

0.0014 x 9.8 x 4 = 0.5 x 0.0014 x 0.5 x 0.5 + Energy gained by the air molecules

Energy gained by the air molecules = 0.05488 - 0.00000175

                                                           = 0.054878 J

Answer:

0.055 J

Explanation:

We are given that

Mass=m=1.4 g=[tex]1.4\times 10^{-3} kg[/tex]

1 kg=1000 g

h=4 m

v=0.5 m/s

Potential energy=[tex]mgh[/tex]

Where [tex]g=9.8 m/s^2[/tex]

Using the  formula

Potential energy of coffee filter lost=[tex]1.4\times 10^{-4}\times 9.8\times 4=5.5\times 10^{-2} J[/tex]

Kinetic energy of coffee filter gain=[tex]\frac{1}{2}mv^2=\frac{1}{2}(1.4\times 10^{-3})\times (0.5)^2=1.75\cdot 10^{-4} J[/tex]

Kinetic energy gain by air molecules from the falling coffee filter=Potential energy-Kinetic energy

Kinetic energy gain by air molecules from the falling coffee filter=[tex]5.5\times 10^{-2}-1.75\times 10^{-4}=0.055 J[/tex]

Hence, the kinetic energy gain by air molecules from the falling coffee filter=0.055 J

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