Question

A girl is sitting in a sled sliding horizontally along some snow (there is friction present).

The normal force supporting the girl and sled is 636 N.

If the coefficient of static friction is 0.38, and the coefficient of kinetic friction between snow and sled is 0.25, what is the force of friction exerted on the sled?

Answer 1

Answer:

159 N

Explanation:

In this problem, the sled is in motion: this means that the force acting on the sled is the force of kinetic friction (while the force of static friction acts when the object is at rest).

The force of kinetic friction is given by:

$F_f = \mu_k N$

where

$\mu_k$ is the coefficient of kinetic friction

N is the normal force on the object

In this problem, we have

$\mu_k = 0.25$ is the coefficient of kinetic friction

N = 636 N is the normal force

So, the force of friction on the sled is:

$F_f = (0.25)(636)=159 N$