4. In a closed system consisting of a cannon and a cannonball, the kinetic energy of a cannon is 72,000 J. If the cannonball is 18 kg it has a velocity of 23 m/s when fired from the cannon, what is the total kinetic energy in the system? A. 72, 207 J
B. 71, 793 J
C. 67, 239 J
D. 76, 761 J

5. In a computational model of the energy loss of a house, if the energy flux increases and the total area insulated increases, what happens to the energy loss of the house?

A. The energy loss must decrease.
B. The energy loss must increase.
C. The energy loss can increase or decrease.
D. The energy loss will neither increase nor decrease.