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

Examine the equation. 23490th→23088ra+42he what kind of barrier would you need to block the radioactive particles from this reaction? a. a piece of paper b. a sheet of aluminum foil c. a two-inch block of lead d. a solid concrete block

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?

What happens when the vapor pressure of a liquid is equal to the external pressure?