35. ssm A 55.0-kg skateboarder starts out with a speed of 1.80 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 nonconservative. The final speed of the skateboarder is 6.00 m/s. (a) Calculate the change (APE = PE, – PE,) in the gravitational potential energy. (b) How much has the vertical height of the skater changed, and is the skater above or below the starting point?

35. ssm A 55.0-kg skateboarder starts out with a speed of 1.80 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 nonconservative. The final speed of the skateboarder is 6.00 m/s. (a) Calculate the change (APE = PE, – PE,) in the gravitational potential energy. (b) How much has the vertical height of the skater changed, and is the skater above or below the starting point?