A40kg skier starts at the top of a 12 meter high slope at the bottom she is traveling g 10m/a how much energy does she lose to friction

Energy at top = U = mgh = 40 * 9.8 * 12 = 4704 J

Energy at bottom = 1/2 mv² = 1/2 * 40 * 10² = 4000 / 2 = 2000 J

Energy Lost = Final - Initial = 4704 - 2000 = 2704 J

In short, Your Answer would be 2704 Joules

Hope this helps!