A skier with mass m=60 kg slides off a platform from a heigh...

Question

A skier with mass m=60 kg slides off a platform from a height h=20 m with a horizontal velocity of 20 m/s. The skier lands at point B, where, due to mechanical energy loss, the horizontal velocity after landing is reduced to 10 m/s. The skier then slides to point C, where they come to rest. The distance between points B and C is s=40m. Neglecting air resistanc, calculate the magnitude of the frictional force acting on the skier while sliding on the horizontal surface between points B and C. (Take g = 10m/s²)

Initial Kinetic Energy at the Moment of Takeoff:

At the moment the skier slides off the platform, they have both potential energy due to height and kinetic energy due to horizontal velocity. However, we only need the horizontal component of the velocity for the kinetic energy at this point.

The total initial kinetic energy at point A is:

Potential Energy at the Height of 20 m:

The gravitational potential energy at point A is:

At this point, the total mechanical energy (kinetic + potential) is:

Kinetic Energy at Point B (just after landing):

The skier's horizontal velocity at point B is , so the kinetic energy at point B is:

Loss of Mechanical Energy during the Fall:

The total mechanical energy at the point of landing (just after the fall) is:

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