Question

If there are two objects in thermal equilibrium in one frame, they will be in thermal equilibrium in all frames

• A. True
• B. False

Answer 1

The correct option is A

True

Temperature is invariant with respect to frames of reference. Your "common sense intuition” should also tell you the same. If a thermometer tells you have a ${101}^{\circ }$ F body temperature while you are seated on a park bench, that won't change if you start sprinting. You still have to take the paracetamol!

This is because temperature only depends on the $v_{rms}$ of the molecules defined with respect to the system that contains it. Even if the system is set to motion, the relative velocities of the molecules, and consequently the $v_{rms}$ remains the same