Question

Sledges slide down an ice-covered hill from a height h (Fig.) and stop after having travelled the distance CB. The distance AB is known to be equal to 5. Determine the coefficient of friction k of the sledges on the icy surface over the run DCB.

Answer 1

Explanation:

At the top of the hill, the sledges possess a potential energy E equals to mgh. During the motion, this energy is converted into the work A₁ in overcoming the force of friction along section DC and into the work A₂ in overcoming the force of friction along section CB, i.e., 

E = mgh = A₁ + A₂.

Since l/S < 1, a₁ > 0 and the sledges will move with uniform acceleration along section DC. The acceleration along section CB is a₂ = — kg, and the sledges decelerate uniformly.