Friction Acceleration: Solving for Coefficient and Force Angle

[rogerbrian05]

A 1000N is being pushed across a level floor at a constant speed by a force of 300N at an angle of 20deg below the horizontal as shown in the figure below.
a. What is the coefficient of kinetic friction between the crate and the floor?
b. If the 300N Force is instead pulling the crate at an angle of 20deg above the horizontal as shown in the figure below, what will be the acceleration of the crate?

Homework Equations

The Attempt at a Solution

 

[Enigman]

Plot the diagram and FBD for starters.