Quote by pebbles
1. The problem statement, all variables and given/known data
A flatbed truck is carrying a 20.0kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?
2. Relevant equations
Is the equation to solve for maximum acceleration F s,max= usN * us?

Fsmax = usN. Then use Newton's 2nd law.
3. The attempt at a solution
I was not taught how to do problems like this...not 100% sure what to plug in for usN...I gave it a shot:
The surface is flat, so I guess the normal force=20.0 kg, so I then mulitplied by .40 to get 8 m/s.........ahhhh. I don't know what I'm doing!

20 Kg, is the mass, the normal force is its weight. Use formula that relates weight with mass.