Question

A 50 Kg ski-jumper is at the top of a ski jump at a height of 100m. How much GPE does she have?

Answer 1

Answer:

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 to B 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 kinetic energy at B. Calculate the speed at which the skier arrives at B.

(Takeg=10ms  

−1

)

Step-by-step explanation:

(a) Mass of skier =60kg  

Loss in potential energy =mg(h  

1

​

−h  

2

​

)

60×10×(75−15)

=60×10×60=3.6×10  

4

J

(b) Kinetic energy at B=  

100

75

​

×3.6×70  

4

=27000J

=2.7×10  

4

J  

Kinetic energy =  

2

1

​

mv  

2

 

27000=  

2

1

​

mv  

2

 

27000=  

2

1

​

×60×v  

2

 

v  

2

=  

30

27000

​

=900

V=30/,m/s