Posted by Kelly on .
An extreme skier, starting from rest, coasts down a mountain slope that makes an angle 25.0° with the horizontal. The coefficient of kinetic friction between her skis and the snow is 0.200. She coasts for a distance of 13.8 m before coming to the edge of a cliff. Without slowing down, she skis off the cliff and lands downhill at a point whose vertical distance is 4.50 m below the edge. How fast is she going just before she lands?

physics 
drwls,
First calculate the potential energy decrease per unit mass,
delta PE = g *(13.8 sin25 + 4.50)
Subtract from that the work done against friction while on snow (per unit mass),
g*cos25*0.20*13.8
The result should be the kinetic energy per unit mass when she lands, which is V^2/2
Use that to calculate the final speed, V