Minimum Force for Moving a Sled on a Horizontal Surface

[tutojean]

Homework Statement

A sled is pulled over a horizontal surface where the kinetic coefficient of friction is .20. What is the minimum force necessary to keep the sled moving if its mass is 2 slugs?

Homework Equations

fs = Ns(mg)

The Attempt at a Solution

fs = (.20) (2 slugs) (32)
=12.8

This problem has got me stumped. Please help! Thank You.

 

[rl.bhat]

What is the unit of fs?

 

[tutojean]

I assume 12.8 N

 

[rl.bhat]

I assume 12.8 N

Unit force is N if mass is in kg.