A 45 kg package slides down a 2 m-high ramp. The package starts from rest, and its speed at the bottom is 8 m/s. (d) Use the conservation of energy to calculate the total change in thermal energy of the ramp and the bottom of the package.

Is (d) a negative answer? My solution: mgh-1/2mv^2 (45)(9.8)(2)-(1/2)(45)(8)^2 = 882-1440= -558J