The first law of thermodynamics states that . is this also a statement of the principle of conservation of energy?

yes, the heat added and the change in internal energy of the gas equal the work done by the piston.

yes, the heat that flows into the system is used to change the internal energy of the gas and becomes work done by the piston.

no, the heat that is added to the system is only used to do work.

no, the change in internal energy is the energy lost in the system.

The correct choice is

Yes, the heat that flows into the system is used to change the internal energy of the gas and becomes work done by the piston.

According to first law of thermodynamics,

Q = W + U

where Q = heat flowing into the system

W = work done by the system

U = change in internal energy of the system

hence the total energy remains same all the time which is what the principle of conservation of energy states.

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.