Crate sliding down a ramp

"A 4.00-kg crate slides down a ramp. The ramp is 1.80 m in length and inclined at an angle of 28.0° as shown in the figure. The crate starts from rest at the top, experiences a constant friction force of magnitude 4.50 N, and continues to move a short distance on the horizontal floor after it leaves the ramp.

http://ift.tt/1kpxi4z (figure)

(A) Use energy methods to determine the speed of the crate at the bottom of the ramp.



(B) How far does the crate slide on the horizontal floor if it continues to experience a friction force of magnitude 4.50 N?"





so i solved part A for the speed of the crate at the bottom of the ramp and got 3.54m/s.



Using the speed, i then solved part B for the distance it traveled on the floor and got 5.57m using 1/2*mv² = f_fd

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Then the problem asks, what will be the final speed at the bottom of the ramp if it has an initial speed of .6m/s?



and this is where I get stuck, im not sure how to calculate that into the equation.



Thanks in advanced for the help.