a 56.5 kg skateboarder starts out with a speed of 1.75 m s he does 80.0 j of work on himself by pushing with his feet against the ground in addition friction does 265 j of work on him in both cases the forces doing the work are non conservative the final speed of the skateboarder is 6.00 m s. (a) Calculate the change (ΔPE = PEf-PE0) in the gravitational potential energy. (b) How much has the vertical height of the skater changed?
(c) Is the skater above or below the starting point?