Change in internal energy if 90 J of thermal energy is added to a system, and the system does 30 J of work on the surroundings? A. -130 J

B. -60 J

C. 130 J

D. 60 J

Does the distance travelled by an oscillating mass between times t=0 and t2 equal the displacement of the particle over the same time period if t2> t/2? hint: consider a sine wave starting at t1=0, then consider a closing wave starting at t1=0, for your explanation.