Finding force to push box at constant speed with friction

[tatiana]

Homework Statement

Man pushes a box that is 11.2 kg on a horizontal surface at a constant speed of 3.5 m/s2. Where μ is .20
a)What is the horizontal force rthat the man must apply to maintain the motion
b)If the force of part a is removed, how far does the box slide before coming to rest?

Homework Equations

F=ma
F=μN

The Attempt at a Solution

F=ma
F=11.2(3.5)
F=39.2

then
F=μN
F=(.20)(109.76)... [11.5*9.8]
F=21.95

then to get the total force i added 39.2+21.95 and got a total of 61.152

For part b I would asume that without part a the force would just be 21.95 because it doesn't account for the answerr to part a?

 

[rl.bhat]

Man pushes a box that is 11.2 kg on a horizontal surface at a constant speed of 3.5 m/s2

Constant speed or acceleration?