The discussion revolves around a physics problem involving the motion of a skier descending a frictionless hill. The skier starts with an initial speed and drops a certain height, prompting questions about the conservation of energy and the calculation of final velocity.
The discussion is active, with various approaches being proposed to solve the problem. Some participants have provided calculations, while others have raised questions about the assumptions made and the correctness of the methods used. There is no explicit consensus on the final answer, and participants are engaging in clarifying the application of energy conservation principles.
There are indications of confusion regarding the initial kinetic energy and how it factors into the final calculations. Some participants have noted discrepancies between their results and those found in reference materials.
(1) Please reread the forum rules about posting complete solutions.Retsam said:Use potential energy formula :
E = m*g*(change in height)
E = 60*9.81*20 = 11772 J
So skier loses 11772 J of potentiaql energy on descent, this is all converted into kinetic energy. So using KE formula :
KE = 0.5*m*(v^2)
V = sqrt(KE/0.5*m) = 19.81 m/s
So add the initial velocity to this to get :
5 + 19.81 = 24.81 m/s
That's the increase in KE as the skier goes down the hill. What's the initial KE? Final KE? Final speed?Sucks@Physics said:E = 60*9.81*20 = 11772 J