Physics Question-1?

Question

I believe it is b, just wanted to double check.

A flatbed truck is carrying a 20.0-kg 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?
a. 3.92 m/s squared.
b. 8.00 m/s squared.
c. 78.5 m/s squared.
d. 196 m/s squared.

Answer 1

Ok, the maximum acceleration that the truck and block can be moving, with the block not sliding is the point at which the force of the acceleration is = to the force of friction.

So we get F:friction = ma

F:friction = Normal Force (u) where u is the friction coefficient, and the Normal force = mg, so we get

umg = ma, and the m cancels out on both sides, leaving you

ug = a

(9.8) (20) (0.4) = (20) a

a = 3.92