Applying Newton's Laws; coefficient of kinetic force

[pinkpony]

Homework Statement

To move a large crate across a rough floor, you push on it with a force F at an angle of 21°, below the horizontal. Find the acceleration of the crate, given that the mass of the crate is m = 28 kg, the applied force is 322 N and the coefficient of kinetic friction between the crate and the floor is 0.50.

Homework Equations

a=g(sinθ-μkcosθ)

μk=-a/g

The Attempt at a Solution

a=9.81(0.836655639-(.5)(-0.54772926)
a=10.8942038m/s²

 

[PhanthomJay]

Homework Statement

To move a large crate across a rough floor, you push on it with a force F at an angle of 21°, below the horizontal. Find the acceleration of the crate, given that the mass of the crate is m = 28 kg, the applied force is 322 N and the coefficient of kinetic friction between the crate and the floor is 0.50.

Homework Equations

The Attempt at a Solution

Please list your relevant equations and attempt at a solution. Then someone will be glad to assist, once you show your work.