Apuck is sliding on a frictionless, level surface in a circle at a constant speed. the required inward acceleration is provided by a spring of force constant k and unstretched length l0. in order to provide the needed force, the spring is stretched a distance ∆l.
~v
as the puck of mass m goes through a complete circle, how much work does the spring do on it?

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.