A skier starts from rest at the top of a 40.8 m hill, skis down a 30 degree incline into a valley, and continues up a 32.5 m high hill. The heights of both hills are measured from the valley floor. Assume that you can neglect friction and the effect of the ski poles. How fast is the skier moving at he bottom of the valley? What is the skier's speed at the top of the next hill? Do the angles of the hills affect your answers?

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Physics

2 August, 03:43

A skier starts from rest at the top of a 40.8 m hill, skis down a 30 degree incline into a valley, and continues up a 32.5 m high hill. The heights of both hills are measured from the valley floor. Assume that you can neglect friction and the effect of the ski poles. How fast is the skier moving at he bottom of the valley? What is the skier's speed at the top of the next hill? Do the angles of the hills affect your answers?

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Answers (1)

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Gina Wolfe · Answer 1

a. 28.27 m/s

b. 12.75 m/s

c. No

Explanation:

a.

The bottom

Ek = Ep

¹/₂ * m * v² = m * g * h₁

v = √ 2 * g * h₁ = √ 2 * 9.8 * 40.8 m

v = 28.27 m/s

b.

At the top

Ek = Ep

¹/₂ * m * v² = m * g * h₁

v = √ 2 * g * h₁ = √ 2 * 9.8 * (40.8 - 32.5) m

v = 12.75 m/s

c.

No in this case the axis is the same of the motion so, the angle doesn't affect the result