<u>Explanation:</u>
5 Horsepower for 30 mins,
(5)(745.7) = 3.7285 KW power delivered
General Efficiency of IC engine = 20%
Power required = ![\frac{3 \cdot 7285}{0 \cdot 2}=18 \cdot 6425 kw](https://tex.z-dn.net/?f=%5Cfrac%7B3%20%5Ccdot%207285%7D%7B0%20%5Ccdot%202%7D%3D18%20%5Ccdot%206425%20kw)
Energy required per week,
=P × Time = 18.64 × 60 × 30 = 33.5565 MJ
Lawn area = (30) (20) = 600![m^{2}](https://tex.z-dn.net/?f=m%5E%7B2%7D)
let sunlight hours be 8 hours
Hence, solar power input on lawn,
=5.62×3600 = 20232 kJ/
/day
energy input in lawn = (600) (20232) (7)
= 84974.4 mJ/week
Chemical efficiency by photosynthesis = 4%
Chemical content in grass = (84974.4) (0.04)
= 3398.97 mJ
Mass of the clippers ![\(=(30)(20)(1 \cdot 096)^{2}(667)\)](https://tex.z-dn.net/?f=%5C%28%3D%2830%29%2820%29%281%20%5Ccdot%20096%29%5E%7B2%7D%28667%29%5C%29)
pounds
Removing water content,
dried grass clippings ![\(=95726.46\) pound](https://tex.z-dn.net/?f=%5C%28%3D95726.46%5C%29%20pound)
= 11533.25 gallons
Trash cans repaired
![=\frac{11533}{50} =230.66\\=231 cans](https://tex.z-dn.net/?f=%3D%5Cfrac%7B11533%7D%7B50%7D%20%3D230.66%5C%5C%3D231%20cans)
By burning the gas, total energy input = 3398.97 MJ × 0.2
= 679.794 MJ
Efficiency of steeling engine = 20%
Energy output by engine = 679.794 ×0.2
= 135.96 mJ
Energy required by mover = 33.5565 mJ
Hence, Energy (output) ⇒ energy required