The heating value of a Gas is 39MJm-3

a) If 4.5m-3 of the gas is burned how much energy is released?

b) If the gas is burned in 5 minutes what is the power?

c) If the burning occurs in an engine that converts the energy to forward
motion and the engine is 20% efficient in converting the heat energy: what is
the kinetic energy a vehicle would have after burning the above quantity of
gas? – (assume no losses due to friction or air resistance)

a) Do you mean 4.5 m-3 or

4.5*10^-3 m^3 ?

The number you wrote is not a volume

I'm not sure, it says 4.5 m^-3

4.5/m^3 just is not volume. Assume it meant 4.5m3.

Then energy= heatvalue*volume=39MJ/m^3*4.5m^3=you do it.

To solve these questions, we need to apply some basic formulas and calculations. Let's break down each question one by one:

a) To calculate the energy released, we can use the formula: Energy released = Heating value of the Gas × Volume of gas burned.

Given:
Heating value of the Gas = 39 MJ/m^3
Volume of gas burned = 4.5 m^3

Energy released = 39 MJ/m^3 × 4.5 m^3 = 175.5 MJ

Therefore, when 4.5 m^3 of gas is burned, 175.5 MJ of energy is released.

b) Power is defined as the amount of energy transferred or converted per unit time. To calculate the power, we can use the formula: Power = Energy / Time.

Given:
Energy released = 175.5 MJ
Time = 5 minutes = 5 × 60 seconds = 300 seconds

Power = 175.5 MJ / 300 s = 0.585 MJ/s or 585 kW

Therefore, the power when burning the gas for 5 minutes is 0.585 MJ/s or 585 kW.

c) Efficiency is defined as the ratio of output energy to input energy. In this case, the output energy is the kinetic energy of the vehicle, and the input energy is the energy released from burning the gas.

Given:
Energy released = 175.5 MJ
Efficiency = 20%

Output Energy (Kinetic Energy of the vehicle) = Efficiency × Energy released

Output Energy = 0.2 × 175.5 MJ = 35.1 MJ

Therefore, the kinetic energy a vehicle would have after burning the quantity of gas is 35.1 MJ.