- #1

kchurchi

- 39

- 0

## Homework Statement

A 290-N crate rides without constraints on the horizontal floor of a truck. The coefficient of static friction and the coefficient of kinetic friction between the crate and the truck are 0.32 and 0.16, respectively. If the truck is initially traveling at 18 m/s, what minimal length of road is needed for it to stop without having the crate slide?

## Homework Equations

Ʃ F(net) = m*a

## The Attempt at a Solution

I drew free body diagrams of the crate, of the truck, and of the crate plus the truck. I plan on using the x-acceleration to solve for a velocity expression. When I set that velocity expression equal to zero I can find the time it takes to stop. I can use this time to find the distance. HOWEVER I can't figure out my friction force. The only force I got acting in the x-direction is friction from the truck on the crate or from the crate on the truck. I know it isn't kinetic friction because it doesn't slip, but I don't know what to do? Help!