The transfer of thermal energy is a major aspect of which branch of physics?
a. mechanics

b. electrostatics

c. thermodynamics

d. quantum mechanics

Mechanics is dealing with forces that are effecting some body, electrostatics is about electrical fields of not moving bodies, and quantum mechanics is dealing with quantum states of atoms. 

Thermodynamics as the word say, is dealing with thermal energy that is moving (transferring from one body to another or even better from one medium to another).

Answer is C 

3x + 2x = both people using the same measure of like 5x = x= 25 meters per second. 25ms. it takes them 4 seconds to