Question

The kinetic energy of a skier at a small hill (Point A) and his potential energy are 120 kJ and 450 kJ, respectively. Then the skier slides down the smooth snow-covered hill to the flat leveled ground with snow. When he reaches the ground level, he continues to ski. When the work done to frictional force between his skis and the ground surface is 50 kJ, what is his kinetic energy in kJ?

Answer 1

$E_k=120+450-50=520\ (kJ)$