Identify each process labeled in the diagram

When objects are charged by they do not need to touch each other. a. friction b. induction c. conduction d. all of these

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

What is tan(61)? а. 1.80 b. 0.49 c. 0.61 d. 0.87