Just answer this question : is the total mechanical energy conserved? What about
ID: 1438074 • Letter: J
Question
Just answer this question : is the total mechanical energy conserved? What about the total system energy? Why or why not?
Class 25: Form A. Skateboarder and spring A performer on a skateboard is launched by a spring initially compressed a distance as shown. His speed on the horizontal portion of the ramp is v, and he rises to a height H after he leaves the ramp. Do NOT ignore friction effects. Ax hwW13 Draw an energy bar chart for the earth-skateboarder- spring system as he goes from the compressed spring 1.Explanation / Answer
The performer on skateboard launched by a spring initally compressed a distanc delta x or Dx.
due to restoring force in the spring the elastic potential energy in the spring is U = 1/2 kx^2, this will be impart to the performer
so that he can move with velocity v on horizontal having kinetic energy of 1/2 mv^2, and reaches a height ,as the kinetic energy converted completely in to potential energy, if so the total mechanical energy will be conserved.
but given that friction should alos considered then the energy f the system will not conserved
1/2 k Dx^2 = 1/2 mv^2- mue_s*mg = mgH- mue_k*mg
as friction force acting here the energy will goes on decreases as it move from the spring , if we draw a graph energy vs positions 1,2,3
initially at position 1 energy is maximum and due to friction it will decrease when it reaches position 2, and still the friction is acting and the performer moving upward against the gravitational force still the energy decreases , so the curve would be a negative slope .
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