In a closed system that has 85 J of mechanical energy, the gravitational potential energy of a weight being lowered by a pulley decreases from 12 J to
9 J. How does the system's kinetic energy change if there is no friction?
O A. It decreases from 76 J to 73 J.
O B. It increases from 85 J to 94 J.
O c. It decreases from 85 J to 76 J.
O D. It increases from 73 J to 76 J.

The starship enterprise is caught in a time warp and spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. the 125-g sample was heated to 96.3°c and placed into a calorimeter containing 85.9 g of water at 20.0°c. the heat capacity of the calorimeter was 14.2 j/k. the final temperature in the calorimeter was 24.5°c. what is the specific heat capacity (in j/g°c) of the mineral? enter to 4 decimal places.