By using a woodstove, the kilograms of wood required to
heat a room to 20°C is 3 kg
<h3>Efficiency of a machine</h3>
- Efficiency is the percent of work put into a machine (input work) to that of the work done by the machine (output work).
- Efficiency of a machine is always less than 100% because the output work is always less than the input work because some of the input work is used to overcome friction.
Efficiency = work output/work input * 100%
Efficiency of fireplaces = 15%
Amount of food required to heat a room to 20°C = 15 kg
Assuming efficiency of 100%, amount of wood required will be X kg:
X = 15% * 15 kg
X = 2.25 Kg
By switching to woodstoves which are 75% efficient, amount of wood required will be Y kg:
Y = 2.25 kg / 75%
Y = 3 kg
Therefore, by using a woodstove, the kilograms of wood required to
heat a room to 20°C is 3 kg
Learn more about efficiency of machines at: brainly.com/question/3617034
