a. The value of H is 11.51 m
b. The total kinetic energy as she reaches the ground is 6.21 kJ.
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
Given is a skier (m=55.0 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally. Value of h = 6.50 m and D = 11.4 m.
Time taken to reach the ground after take off is
t = √2h/g
t = √(2x6.50) /9.81
t =1.15 s
The speed at that time is
speed = distance /time
v = 11.4 /1.15
v = 9.913 m/s
a. From energy conservation principle,
v = √2g(H-h)
Plug the values, we get
9.913 = √(2 x 9.81 (H - 6.5)
Squaring both sides and solving, we have
H = 11.51 m
Thus, the value of H is 11.51 m.
b. The energy at the ground will be only potential energy
Total kinetic energy at the ground = mgH
T.K.E = 55 x 9.81 x 11.51
T.K.E =6.21 kJ
Thus, the total kinetic energy is 6.21 kJ.
Learn more about mechanical energy.
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