Calculating Speed on a Snow Sled with Frictional Force

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The discussion revolves around calculating the speed of a person on a snow sled descending from a height of 24.0m, factoring in a frictional force of 70.0 N. The relevant equations include potential energy (PE) and kinetic energy (KE), leading to the equation mgh = 1/2mv² + W, where W represents work done against friction. An initial calculation suggested a speed of 66.77 m/s, but confusion arose regarding the use of the spring equation for energy lost due to friction. Participants emphasized the importance of proper dimensional analysis and correctly applying the work done formula. Accurate calculations are essential for determining the sled's final speed at the bottom of the hill.
hatcheezy
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Homework Statement


A person on a snow sled(total mass of 60.0kg) starts from rest at a vertical height of 24.0m above the bottem of the hill. If aconstant frictional force of 70.0 N opposes their motion as they slide down the hill and the length of the slope is 65.0m, whta is their speedat the bottem of teh hill?


Homework Equations


PE = KE + W
mgh = 1/2mv2 + 1/2kx2


The Attempt at a Solution


(60kg)(9.8m/s2)(24m) = 1/2(60kg)v2 + 1/2(70N)(65m)2

14112 = 30v2 +147875

v=66.77m/s ??
 
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1/2kx^2? That's the equation for a spring, not for the energy lost due to friction.

Just check your dimensional analysis, your units don't make sense.
 
Recall the equation for Work Done...
 
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