4.One rubber tire can generate about250,000 BTUS (1BTU=.0003KW ) when it is burned. The average American home consumes about 10,000 kWh of electricity per year. How many tires would be needed to meet the annual electricity demand of ten homes for one year if the production of electricity from tires is 50% efficient??

The number of tires required to power ten homes for one year is approximately 2,730 tires

Explanation:

The given information are;

The energy generated by burning one rubber tire = 250,000 BTUs

1 BTU = 0.0003 kW

The amount of energy consumed by the average American home = 10,000 kWh

Therefore, the amount of energy generated by burning one tire in kW can be found as follows;

The energy generated by burning one rubber tire = 250,000 BTUs

1 BTU = 0.0003 kW

∴ 1 BTU × 250,000 = 250,000 BTUs = 0.0003 kW × 250,000 = 75 kW

We note that 250,000 BTUs is equivalent to 263764 kJ

1 kWh is equivalent to 3600 kJ

10,000 kWh = 10,000 × 3600 = 36,000,000 kJ

The energy requirement for ten homes  for one year = 10 × 36,000,000 kJ = 360,000,000 kJ

At 50% efficiency, the energy produced per tire = 0.5 × 263764 kJ = 131,882 kJ

The electrical energy produced per tire = 131,882 kJ/tire

The number of tires required to power ten homes for one year = 360,000,000 kJ/  131,882 kJ/tire = 2,729.71293  ≈2,730 tires

The number of tires required to power ten homes  ≈2,730 tires.