In a heat engine, if 700j of heat enters the system, and the piston does 400j of work, what is the final internal thermal energy of the system if the initial energy is 1200j?

Ahanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. in this situation, we define its position as x = 0. the object is pulled down an additional 18.0 cm and released from rest to oscillate without friction. what is its position x at a moment 84.4 s later? express your answer in cm.