Answer: The efficiency Shelly does is 87.5%.
(70J/80J) x 100% = 87.5%
Answer 2: Gravitational potential energy would be considered an object 10 meters above the ground.
50 μm = 5 × 10⁻⁵ m in diameter
<h3>Steps</h3>
1μm = 1 x
m
<h3>Given</h3>
1μm = 1 x
m
50μm = 50 x
m
50μm = 50 x 10 x 
50μm = 5 x
m
<h3>Conclusion</h3>
A human hair is approximately 50 μm = 5 × 10⁻⁵ m in diameter
<h3>How big is a human hair on average?</h3>
between 17 and 181 micrometers
The typical diameter of human hair can range from 17 micrometers to 181 micrometers, according to research. Using 50 micrometers as an average figure for its diameter, this translates to 50,000 nanometers.
<h3>What is a human hair's diameter in inches?</h3>
The finest hair is flaxen, with a diameter ranging from 1/1500 to 1/500 of an inch. the coarsest hair is black, measuring between 1/450 and 1/140 of an inch.
learn more about human hair diameter here
<u>brainly.com/question/13147893</u>
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Just find the density of every metal and select the one with a density of 2.71 g/cm³ . This is:
Metal 1
ρ = m/V
ρ = 22.1 g / 3 cm³
ρ = 7.367 g / cm³
Metal 2
ρ = m/V
ρ = 42 g / 4 cm³
ρ = 10.5 g / cm³
Metal 3
ρ = m/V
ρ = 9.32 g / 5 cm³
ρ = 1.864 g / cm³
Metal 4
ρ = m/V
ρ = 8.13 g / 3 cm³
ρ = 2.71 g / cm³
<h2>R / Metal 4 was selected.</h2>
I think the answer would be
C.Electrons
Hope this helps
The electrons are in the electron cloud the different field will either wanna connect or not