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Home » The diagram given below shows a ski jump. A skier weighing 60kgf stands at A at the top of ski jump. He moves from A and takes off for his jump at B.
The diagram given below shows a ski jump. A skier weighing 60kgf stands at A at the top of ski jump. He moves from A and takes off for his jump at B.
Class 10 | ICSE | Physics | Selina | Work Energy
The diagram given below shows a ski jump. A skier weighing 60kgf stands at A at the top of ski jump. He moves from A and takes off for his jump at B.

(a)Calculate the change in the gravitational potential energy of the skier between A and B.

(b)If 75% of the energy in part (a) becomes the kinetic energy at B, calculate the speed at which the skier arrives at B.

(Take g = 10 m s-2).

Solutions:

(a) Mass of skier is 60 kg

Loss in potential energy is given by expression –

= mg (h1 – h2)

= 60 × 10 × (75 – 15) = 60 × 10 × 60

= 3.6 × 104J

(b) Kinetic energy at B is given by –

= 75 / 100 × 3.6 × 104 = 27000J

= 2.7 × 104J

We know that the expression of Kinetic energy is 1 / 2 mv2

27000 = 1 / 2 mv2

Or, 27000 = 1 / 2 × 60 × v2

v2 = 27000 / 30 = 900

v = 30 m / s

i

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