Calculate the coefficient of kinetic friction between the block and the floor.

You will need to find components of forces and write equilibrium conditions to solve for mu.

Is the normal force on the block greater than, less than, or equal to the weight of the crate?  Justify your answer.

Now the speed is doubled, to 8.0 m/s.  

1) Will the new coefficient of friction be greater than, less than, or equal to the coefficient calculated in (b)?  Justify your answer.

2) Will the new force of friction on the crate be greater than, less than, or equal to the previous force of friction on the crate?  Justify your answer.

Don't be shy

What is the most confusing thing in this unit on equilibrium?