The sledder shown inFigure 1starts from the top of a frictionless hill and slides down into the valley. Suppose that h1 = 4.5 m &h2 = 5.8 m?

Question

What initial speed vi does the sledder need to just make it over the next hill?

Express your answer to two significant figures and include the appropriate units.

PLZ HELP ASAP

Answer 1

Conservation of Energy... 

E hill 1  =  E hill 2

E hill 1 =  PE  + KE  =   mg(h1)  + (1/2)m(v1)^2

E hill  2  =    mg(h2)  + (1/2)m(v2)^2   

   v1 = velocity on hill  1           v2 = velocity on hill 2 

 h1  = height  first hill on left         h2 = height hill on the right

         mg(h1)  + (1/2) m (v1)^2     =    mg(h2)  + (1/2) m (v2)^2  

we  know  h1 , h2,   g   

AND      v2 = 0  if you JUST make it to the top of the hill #2

 Notice  m  cancels out on both sides   !

Now  solve  for   v1 ... I got an answer between  5  to 6 m/s   .............   You do the work.

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