what is the mass of a rock on the edge of a 40m cliff with 980 joules of potential energy?



calculate a hammer's PEi with a KEi of 0J, a PEf of 10j, and a KEf of 185 J.


if a 2kg bowling balls PEi is 100j and KEi is 21J, what is its final potential energy if it strikes the pins traveling at 6m/s?



please show work with units