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Q&A: Using energy conservation to find the maximum height?

Question by : Using energy conservation to find the maximum height?
A 65.0 kg skier approaches the foot of a hill with a speed of 16.0 m/s. The surface of this hill slopes up at 55.0 degrees above the horizontal and has coefficients of static and kinetic friction of 0.750 and 0.250, respectively, with the skis.

Use energy conservation to find the maximum height above the foot of the hill that the skier will reach.

Best answer:

Answer by TBT
initial KE
= 0.5 * 65 * 16^2 J

let h be the maximum height above the foot of the hill that the skier will reach

normal force due to weight
= 65 *g * cos 55
friction force
= 0.25 * 65 *g * cos 55
length travelled
= h /sin 55

final PE + work done due to friction
= 65 * g * h +0.25 * 65 *g * cos 55 * h /sin 55

65 * 9.81 * h + 0.25 * 65 *9.81 * cos 55 * h /sin 55 = 0.5 * 65 * 16^2
637.65 h + 111.59 h = 8320
h = 11.1 m —answer

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