a skier starts at the top of a hill this hill is 100 meters in the air the hill is pictured below the skier has a mass of about 50kg using the law of conversation of energy determine the Pe and Ke at the various points a he is at his maximum height and not moving at point E he has come to a complete stop

a)  Em = Pe = 4.9 10⁴ J,  b)   K = 2.05 10⁴ J , c)     K = 3.92  104 J ,

e)  W_ friction = Em = 4.9 10⁴ J  

Explanation:

The skier goes down the slope if we assume that there is no friction, the mechanical energy is conserved

         Em = PE + K

where the potential energy is

         PE = m g h

the kinetic energy is

         K = ½ m v²

Let's write the mechanical energy at various points

a) Point A. It is the highest point of the entire system and as the skier is leaving his speed is zero

           Em = Pe

           Em = m g h

let's calculate

           Em = 50 9.8 100

           Em = 4.9 10⁴ J

b) Point B. This point is 60 m

          Em = Pe + K

          K = Em - Pe

          K = 4.9 10⁴ - m g h_B

          K = 4.9   10⁴ - 5 9.8 60

          K = 4.9 10⁴ - 2.85 10⁴

          K = 2.05 10⁴ J

c) point c. This point is 20 m

          Em = Pe + K

          K = Em -Pe = 4.9 10⁴ J - m g h_c

          K = 4.9 10⁴ - 50 9.8 20  = 4.9 10⁴ -  9800

          K = 3.92  104 J

d) point d. It is at a height of 60 m

           Em = Pe + K

           K = Em -Pe

           K = 4.9 10⁴ - m g h

           K = 4.9 10⁴ - 50 9.8 60 =4.9 104 - 2.94 10⁻⁴

           K = 4.897 104 J

e) point E. In this part they indicate that the body is stopped, therefore in this flat part it must be friction so that a device work is carried out that makes the understanding transform into heat by friction and the system stops

            W_ friction = Em = 4.9 10⁴ J

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be