A gas in a closed container is heated with 12J of energy, causing the lid of the container to rise 3m with 5N of force. What is the total change in energy?

27J

Explanation:

From conservation of Thermal energy, the total internal energy is the total sum of energy supplied or taken from the system plus work done for or on the system.

Now the change in internal energy would be the sum of the received energy substended in the gas plus the work done by the system which is workdone that it will sustend in pushing the lid. This is expressed mathematically as;

U = Q + (F*d);

U - change in internal energy

Q is the energy received by the system and is positive when energy is received by the system.

Fxd is the workdone and is positive since the gas pushes up the lid - the system does work.

U=12 + (3*5) = 27J