Laws of Motion on a snow sled

  • #1

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 ??
  • #2
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.
  • #3
Recall the equation for Work Done...

Suggested for: Laws of Motion on a snow sled